--- a/net/minecraft/world/entity/Entity.java
+++ b/net/minecraft/world/entity/Entity.java
@@ -136,6 +_,108 @@
 import org.slf4j.Logger;
 
 public abstract class Entity implements SyncedDataHolder, Nameable, EntityAccess, ScoreHolder {
+
+    // CraftBukkit start
+    private static final int CURRENT_LEVEL = 2;
+    public boolean preserveMotion = true; // Paper - Fix Entity Teleportation and cancel velocity if teleported; keep initial motion on first setPositionRotation
+    static boolean isLevelAtLeast(CompoundTag tag, int level) {
+        return tag.contains("Bukkit.updateLevel") && tag.getInt("Bukkit.updateLevel") >= level;
+    }
+
+    // Paper start - Share random for entities to make them more random
+    public static RandomSource SHARED_RANDOM = new RandomRandomSource();
+    private static final class RandomRandomSource extends java.util.Random implements net.minecraft.world.level.levelgen.BitRandomSource {
+        private boolean locked = false;
+
+        @Override
+        public synchronized void setSeed(long seed) {
+            if (locked) {
+                LOGGER.error("Ignoring setSeed on Entity.SHARED_RANDOM", new Throwable());
+            } else {
+                super.setSeed(seed);
+                locked = true;
+            }
+        }
+
+        @Override
+        public RandomSource fork() {
+            return new net.minecraft.world.level.levelgen.LegacyRandomSource(this.nextLong());
+        }
+
+        @Override
+        public net.minecraft.world.level.levelgen.PositionalRandomFactory forkPositional() {
+            return new net.minecraft.world.level.levelgen.LegacyRandomSource.LegacyPositionalRandomFactory(this.nextLong());
+        }
+
+        // these below are added to fix reobf issues that I don't wanna deal with right now
+        @Override
+        public int next(int bits) {
+            return super.next(bits);
+        }
+
+        @Override
+        public int nextInt(int origin, int bound) {
+            return net.minecraft.world.level.levelgen.BitRandomSource.super.nextInt(origin, bound);
+        }
+
+        @Override
+        public long nextLong() {
+            return net.minecraft.world.level.levelgen.BitRandomSource.super.nextLong();
+        }
+
+        @Override
+        public int nextInt() {
+            return net.minecraft.world.level.levelgen.BitRandomSource.super.nextInt();
+        }
+
+        @Override
+        public int nextInt(int bound) {
+            return net.minecraft.world.level.levelgen.BitRandomSource.super.nextInt(bound);
+        }
+
+        @Override
+        public boolean nextBoolean() {
+            return net.minecraft.world.level.levelgen.BitRandomSource.super.nextBoolean();
+        }
+
+        @Override
+        public float nextFloat() {
+            return net.minecraft.world.level.levelgen.BitRandomSource.super.nextFloat();
+        }
+
+        @Override
+        public double nextDouble() {
+            return net.minecraft.world.level.levelgen.BitRandomSource.super.nextDouble();
+        }
+
+        @Override
+        public double nextGaussian() {
+            return super.nextGaussian();
+        }
+    }
+    // Paper end - Share random for entities to make them more random
+    public org.bukkit.event.entity.CreatureSpawnEvent.SpawnReason spawnReason; // Paper - Entity#getEntitySpawnReason
+
+    private org.bukkit.craftbukkit.entity.CraftEntity bukkitEntity;
+
+    public org.bukkit.craftbukkit.entity.CraftEntity getBukkitEntity() {
+        if (this.bukkitEntity == null) {
+            // Paper start - Folia schedulers
+            synchronized (this) {
+                if (this.bukkitEntity == null) {
+                    return this.bukkitEntity = org.bukkit.craftbukkit.entity.CraftEntity.getEntity(this.level.getCraftServer(), this);
+                }
+            }
+            // Paper end - Folia schedulers
+        }
+        return this.bukkitEntity;
+    }
+    // Paper start
+    public org.bukkit.craftbukkit.entity.CraftEntity getBukkitEntityRaw() {
+        return this.bukkitEntity;
+    }
+    // Paper end
+
     private static final Logger LOGGER = LogUtils.getLogger();
     public static final String ID_TAG = "id";
     public static final String PASSENGERS_TAG = "Passengers";
@@ -196,7 +_,7 @@
     public double zOld;
     public boolean noPhysics;
     private boolean wasOnFire;
-    public final RandomSource random = RandomSource.create();
+    public final RandomSource random = SHARED_RANDOM; // Paper - Share random for entities to make them more random
     public int tickCount;
     private int remainingFireTicks = -this.getFireImmuneTicks();
     public boolean wasTouchingWater;
@@ -233,7 +_,7 @@
     protected UUID uuid = Mth.createInsecureUUID(this.random);
     protected String stringUUID = this.uuid.toString();
     private boolean hasGlowingTag;
-    private final Set<String> tags = Sets.newHashSet();
+    private final Set<String> tags = new io.papermc.paper.util.SizeLimitedSet<>(new it.unimi.dsi.fastutil.objects.ObjectOpenHashSet<>(), MAX_ENTITY_TAG_COUNT); // Paper - fully limit tag size - replace set impl
     private final double[] pistonDeltas = new double[]{0.0, 0.0, 0.0};
     private long pistonDeltasGameTime;
     private EntityDimensions dimensions;
@@ -250,6 +_,63 @@
     private final List<Entity.Movement> movementThisTick = new ArrayList<>();
     private final Set<BlockState> blocksInside = new ReferenceArraySet<>();
     private final LongSet visitedBlocks = new LongOpenHashSet();
+    // CraftBukkit start
+    public boolean forceDrops;
+    public boolean persist = true;
+    public boolean visibleByDefault = true;
+    public boolean valid;
+    public boolean inWorld = false;
+    public boolean generation;
+    public int maxAirTicks = this.getDefaultMaxAirSupply(); // CraftBukkit - SPIGOT-6907: re-implement LivingEntity#setMaximumAir()
+    @Nullable // Paper - Refresh ProjectileSource for projectiles
+    public org.bukkit.projectiles.ProjectileSource projectileSource; // For projectiles only
+    public boolean lastDamageCancelled; // SPIGOT-5339, SPIGOT-6252, SPIGOT-6777: Keep track if the event was canceled
+    public boolean persistentInvisibility = false;
+    public BlockPos lastLavaContact;
+    // Marks an entity, that it was removed by a plugin via Entity#remove
+    // Main use case currently is for SPIGOT-7487, preventing dropping of leash when leash is removed
+    public boolean pluginRemoved = false;
+    protected int numCollisions = 0; // Paper - Cap entity collisions
+    public boolean fromNetherPortal; // Paper - Add option to nerf pigmen from nether portals
+    public boolean spawnedViaMobSpawner; // Paper - Yes this name is similar to above, upstream took the better one
+    // Paper start - Entity origin API
+    @javax.annotation.Nullable
+    private org.bukkit.util.Vector origin;
+    @javax.annotation.Nullable
+    private UUID originWorld;
+    public boolean freezeLocked = false; // Paper - Freeze Tick Lock API
+    public boolean fixedPose = false; // Paper - Expand Pose API
+    private final int despawnTime; // Paper - entity despawn time limit
+    public final io.papermc.paper.entity.activation.ActivationType activationType = io.papermc.paper.entity.activation.ActivationType.activationTypeFor(this); // Paper - EAR 2/tracking ranges
+
+    public void setOrigin(@javax.annotation.Nonnull org.bukkit.Location location) {
+        this.origin = location.toVector();
+        this.originWorld = location.getWorld().getUID();
+    }
+
+    @javax.annotation.Nullable
+    public org.bukkit.util.Vector getOriginVector() {
+        return this.origin != null ? this.origin.clone() : null;
+    }
+
+    @javax.annotation.Nullable
+    public UUID getOriginWorld() {
+        return this.originWorld;
+    }
+    // Paper end - Entity origin API
+    public float getBukkitYaw() {
+        return this.yRot;
+    }
+
+    public boolean isChunkLoaded() {
+        return this.level.hasChunk((int) Math.floor(this.getX()) >> 4, (int) Math.floor(this.getZ()) >> 4);
+    }
+    // CraftBukkit end
+    // Paper start
+    public final AABB getBoundingBoxAt(double x, double y, double z) {
+        return this.dimensions.makeBoundingBox(x, y, z);
+    }
+    // Paper end
 
     public Entity(EntityType<?> entityType, Level level) {
         this.type = entityType;
@@ -271,6 +_,7 @@
         this.entityData = builder.build();
         this.setPos(0.0, 0.0, 0.0);
         this.eyeHeight = this.dimensions.eyeHeight();
+        this.despawnTime = type == EntityType.PLAYER ? -1 : level.paperConfig().entities.spawning.despawnTime.getOrDefault(type, io.papermc.paper.configuration.type.number.IntOr.Disabled.DISABLED).or(-1); // Paper - entity despawn time limit
     }
 
     public boolean isColliding(BlockPos pos, BlockState state) {
@@ -284,6 +_,12 @@
         return team != null && team.getColor().getColor() != null ? team.getColor().getColor() : 16777215;
     }
 
+    // CraftBukkit start - SPIGOT-6907: re-implement LivingEntity#setMaximumAir()
+    public int getDefaultMaxAirSupply() {
+        return Entity.TOTAL_AIR_SUPPLY;
+    }
+    // CraftBukkit end
+
     public boolean isSpectator() {
         return false;
     }
@@ -324,7 +_,7 @@
     }
 
     public boolean addTag(String tag) {
-        return this.tags.size() < 1024 && this.tags.add(tag);
+        return this.tags.add(tag); // Paper - fully limit tag size - replace set impl
     }
 
     public boolean removeTag(String tag) {
@@ -332,12 +_,18 @@
     }
 
     public void kill(ServerLevel level) {
-        this.remove(Entity.RemovalReason.KILLED);
+        this.remove(Entity.RemovalReason.KILLED, org.bukkit.event.entity.EntityRemoveEvent.Cause.DEATH); // CraftBukkit - add Bukkit remove cause
         this.gameEvent(GameEvent.ENTITY_DIE);
     }
 
     public final void discard() {
-        this.remove(Entity.RemovalReason.DISCARDED);
+        // CraftBukkit start - add Bukkit remove cause
+        this.discard(null);
+    }
+
+    public final void discard(org.bukkit.event.entity.EntityRemoveEvent.Cause cause) {
+        this.remove(Entity.RemovalReason.DISCARDED, cause);
+        // CraftBukkit end
     }
 
     protected abstract void defineSynchedData(SynchedEntityData.Builder builder);
@@ -346,6 +_,48 @@
         return this.entityData;
     }
 
+    // CraftBukkit start
+    public void refreshEntityData(ServerPlayer to) {
+        List<SynchedEntityData.DataValue<?>> list = this.entityData.packAll(); // Paper - Update EVERYTHING not just not default
+
+        if (list != null && to.getBukkitEntity().canSee(this.getBukkitEntity())) { // Paper
+            to.connection.send(new net.minecraft.network.protocol.game.ClientboundSetEntityDataPacket(this.getId(), list));
+        }
+    }
+    // CraftBukkit end
+    // Paper start
+    // This method should only be used if the data of an entity could have become desynced
+    // due to interactions on the client.
+    public void resendPossiblyDesyncedEntityData(net.minecraft.server.level.ServerPlayer player) {
+        if (player.getBukkitEntity().canSee(this.getBukkitEntity())) {
+            ServerLevel world = (net.minecraft.server.level.ServerLevel)this.level();
+            net.minecraft.server.level.ChunkMap.TrackedEntity tracker = world == null ? null : world.getChunkSource().chunkMap.entityMap.get(this.getId());
+            if (tracker == null) {
+                return;
+            }
+            final net.minecraft.server.level.ServerEntity serverEntity = tracker.serverEntity;
+            final List<net.minecraft.network.protocol.Packet<? super net.minecraft.network.protocol.game.ClientGamePacketListener>> list = new java.util.ArrayList<>();
+            serverEntity.sendPairingData(player, list::add);
+            player.connection.send(new net.minecraft.network.protocol.game.ClientboundBundlePacket(list));
+        }
+    }
+
+    // This method allows you to specifically resend certain data accessor keys to the client
+    public void resendPossiblyDesyncedDataValues(List<EntityDataAccessor<?>> keys, ServerPlayer to) {
+        if (!to.getBukkitEntity().canSee(this.getBukkitEntity())) {
+            return;
+        }
+
+        final List<SynchedEntityData.DataValue<?>> values = new java.util.ArrayList<>(keys.size());
+        for (final EntityDataAccessor<?> key : keys) {
+            final SynchedEntityData.DataItem<?> synchedValue = this.entityData.getItem(key);
+            values.add(synchedValue.value());
+        }
+
+        to.connection.send(new net.minecraft.network.protocol.game.ClientboundSetEntityDataPacket(this.id, values));
+    }
+    // Paper end
+
     @Override
     public boolean equals(Object object) {
         return object instanceof Entity && ((Entity)object).id == this.id;
@@ -357,7 +_,13 @@
     }
 
     public void remove(Entity.RemovalReason reason) {
-        this.setRemoved(reason);
+        // CraftBukkit start - add Bukkit remove cause
+        this.setRemoved(reason, null);
+    }
+
+    public void remove(Entity.RemovalReason reason, org.bukkit.event.entity.EntityRemoveEvent.Cause eventCause) {
+        this.setRemoved(reason, eventCause);
+        // CraftBukkit end
     }
 
     public void onClientRemoval() {
@@ -367,7 +_,18 @@
     }
 
     public void setPose(Pose pose) {
-        this.entityData.set(DATA_POSE, pose);
+        if (this.fixedPose) return; // Paper - Expand Pose API
+        // CraftBukkit start
+        if (pose == this.getPose()) {
+            return;
+        }
+        // Paper start - Don't fire sync event during generation
+        if (!this.generation) {
+            this.level.getCraftServer().getPluginManager().callEvent(new org.bukkit.event.entity.EntityPoseChangeEvent(this.getBukkitEntity(), org.bukkit.entity.Pose.values()[pose.ordinal()]));
+        }
+        // Paper end - Don't fire sync event during generation
+        // CraftBukkit end
+        this.entityData.set(Entity.DATA_POSE, pose);
     }
 
     public Pose getPose() {
@@ -390,6 +_,32 @@
     }
 
     public void setRot(float yRot, float xRot) {
+        // CraftBukkit start - yaw was sometimes set to NaN, so we need to set it back to 0
+        if (Float.isNaN(yRot)) {
+            yRot = 0;
+        }
+
+        if (yRot == Float.POSITIVE_INFINITY || yRot == Float.NEGATIVE_INFINITY) {
+            if (this instanceof ServerPlayer) {
+                this.level.getCraftServer().getLogger().warning(this.getScoreboardName() + " was caught trying to crash the server with an invalid yaw");
+                ((org.bukkit.craftbukkit.entity.CraftPlayer) this.getBukkitEntity()).kickPlayer("Infinite yaw (Hacking?)");
+            }
+            yRot = 0;
+        }
+
+        // pitch was sometimes set to NaN, so we need to set it back to 0
+        if (Float.isNaN(xRot)) {
+            xRot = 0;
+        }
+
+        if (xRot == Float.POSITIVE_INFINITY || xRot == Float.NEGATIVE_INFINITY) {
+            if (this instanceof ServerPlayer) {
+                this.level.getCraftServer().getLogger().warning(this.getScoreboardName() + " was caught trying to crash the server with an invalid pitch");
+                ((org.bukkit.craftbukkit.entity.CraftPlayer) this.getBukkitEntity()).kickPlayer("Infinite pitch (Hacking?)");
+            }
+            xRot = 0;
+        }
+        // CraftBukkit end
         this.setYRot(yRot % 360.0F);
         this.setXRot(xRot % 360.0F);
     }
@@ -399,8 +_,8 @@
     }
 
     public void setPos(double x, double y, double z) {
-        this.setPosRaw(x, y, z);
-        this.setBoundingBox(this.makeBoundingBox());
+        this.setPosRaw(x, y, z, true); // Paper - Block invalid positions and bounding box; force update
+        // this.setBoundingBox(this.makeBoundingBox()); // Paper - Block invalid positions and bounding box; move into setPosRaw
     }
 
     protected final AABB makeBoundingBox() {
@@ -430,12 +_,28 @@
     }
 
     public void tick() {
+        // Paper start - entity despawn time limit
+        if (this.despawnTime >= 0 && this.tickCount >= this.despawnTime) {
+            this.discard(org.bukkit.event.entity.EntityRemoveEvent.Cause.DESPAWN);
+            return;
+        }
+        // Paper end - entity despawn time limit
         this.baseTick();
     }
 
+    // CraftBukkit start
+    public void postTick() {
+        // No clean way to break out of ticking once the entity has been copied to a new world, so instead we move the portalling later in the tick cycle
+        if (!(this instanceof ServerPlayer) && this.isAlive()) { // Paper - don't attempt to teleport dead entities
+            this.handlePortal();
+        }
+    }
+    // CraftBukkit end
+
     public void baseTick() {
         ProfilerFiller profilerFiller = Profiler.get();
         profilerFiller.push("entityBaseTick");
+        if (firstTick && this instanceof net.minecraft.world.entity.NeutralMob neutralMob) neutralMob.tickInitialPersistentAnger(level); // Paper - Prevent entity loading causing async lookups
         this.inBlockState = null;
         if (this.isPassenger() && this.getVehicle().isRemoved()) {
             this.stopRiding();
@@ -445,7 +_,7 @@
             this.boardingCooldown--;
         }
 
-        this.handlePortal();
+        if (this instanceof ServerPlayer) this.handlePortal(); // CraftBukkit - // Moved up to postTick
         if (this.canSpawnSprintParticle()) {
             this.spawnSprintParticle();
         }
@@ -470,7 +_,7 @@
                     this.setRemainingFireTicks(this.remainingFireTicks - 1);
                 }
 
-                if (this.getTicksFrozen() > 0) {
+                if (this.getTicksFrozen() > 0 && !this.freezeLocked) { // Paper - Freeze Tick Lock API
                     this.setTicksFrozen(0);
                     this.level().levelEvent(null, 1009, this.blockPosition, 1);
                 }
@@ -482,6 +_,10 @@
         if (this.isInLava()) {
             this.lavaHurt();
             this.fallDistance *= 0.5F;
+            // CraftBukkit start
+        } else {
+            this.lastLavaContact = null;
+            // CraftBukkit end
         }
 
         this.checkBelowWorld();
@@ -502,7 +_,12 @@
     }
 
     public void checkBelowWorld() {
-        if (this.getY() < this.level().getMinY() - 64) {
+        if (!this.level.getWorld().isVoidDamageEnabled()) return; // Paper - check if void damage is enabled on the world
+        // Paper start - Configurable nether ceiling damage
+        if (this.getY() < (this.level.getMinY() + this.level.getWorld().getVoidDamageMinBuildHeightOffset()) || (this.level.getWorld().getEnvironment() == org.bukkit.World.Environment.NETHER // Paper - use configured min build height offset
+            && this.level.paperConfig().environment.netherCeilingVoidDamageHeight.test(v -> this.getY() >= v)
+            && (!(this instanceof Player player) || !player.getAbilities().invulnerable))) {
+            // Paper end - Configurable nether ceiling damage
             this.onBelowWorld();
         }
     }
@@ -531,9 +_,24 @@
 
     public void lavaHurt() {
         if (!this.fireImmune()) {
-            this.igniteForSeconds(15.0F);
+            // CraftBukkit start - Fallen in lava TODO: this event spams!
+            if (this instanceof net.minecraft.world.entity.LivingEntity && this.remainingFireTicks <= 0) {
+                // not on fire yet
+                org.bukkit.block.Block damager = (this.lastLavaContact == null) ? null : org.bukkit.craftbukkit.block.CraftBlock.at(this.level, this.lastLavaContact);
+                org.bukkit.entity.Entity damagee = this.getBukkitEntity();
+                org.bukkit.event.entity.EntityCombustEvent combustEvent = new org.bukkit.event.entity.EntityCombustByBlockEvent(damager, damagee, 15);
+                this.level.getCraftServer().getPluginManager().callEvent(combustEvent);
+
+                if (!combustEvent.isCancelled()) {
+                    this.igniteForSeconds(combustEvent.getDuration(), false);
+                }
+            } else {
+                // This will be called every single tick the entity is in lava, so don't throw an event
+                this.igniteForSeconds(15.0F, false);
+            }
+            // CraftBukkit end
             if (this.level() instanceof ServerLevel serverLevel
-                && this.hurtServer(serverLevel, this.damageSources().lava(), 4.0F)
+                && this.hurtServer(serverLevel, this.damageSources().lava().directBlock(this.level, this.lastLavaContact), 4.0F) // CraftBukkit - we also don't throw an event unless the object in lava is living, to save on some event calls
                 && this.shouldPlayLavaHurtSound()
                 && !this.isSilent()) {
                 serverLevel.playSound(
@@ -548,7 +_,23 @@
     }
 
     public final void igniteForSeconds(float seconds) {
-        this.igniteForTicks(Mth.floor(seconds * 20.0F));
+        // CraftBukkit start
+        this.igniteForSeconds(seconds, true);
+    }
+
+    public final void igniteForSeconds(float f, boolean callEvent) {
+        if (callEvent) {
+            org.bukkit.event.entity.EntityCombustEvent event = new org.bukkit.event.entity.EntityCombustEvent(this.getBukkitEntity(), f);
+            this.level.getCraftServer().getPluginManager().callEvent(event);
+
+            if (event.isCancelled()) {
+                return;
+            }
+
+            f = event.getDuration();
+        }
+        // CraftBukkit end
+        this.igniteForTicks(Mth.floor(f * 20.0F));
     }
 
     public void igniteForTicks(int ticks) {
@@ -570,7 +_,7 @@
     }
 
     protected void onBelowWorld() {
-        this.discard();
+        this.discard(org.bukkit.event.entity.EntityRemoveEvent.Cause.OUT_OF_WORLD); // CraftBukkit - add Bukkit remove cause
     }
 
     public boolean isFree(double x, double y, double z) {
@@ -627,6 +_,7 @@
     }
 
     public void move(MoverType type, Vec3 movement) {
+        final Vec3 originalMovement = movement; // Paper - Expose pre-collision velocity
         if (this.noPhysics) {
             this.setPos(this.getX() + movement.x, this.getY() + movement.y, this.getZ() + movement.z);
         } else {
@@ -701,6 +_,28 @@
                     }
                 }
 
+                // CraftBukkit start
+                if (this.horizontalCollision && this.getBukkitEntity() instanceof org.bukkit.entity.Vehicle) {
+                    org.bukkit.entity.Vehicle vehicle = (org.bukkit.entity.Vehicle) this.getBukkitEntity();
+                    org.bukkit.block.Block bl = this.level.getWorld().getBlockAt(Mth.floor(this.getX()), Mth.floor(this.getY()), Mth.floor(this.getZ()));
+
+                    if (movement.x > vec3.x) {
+                        bl = bl.getRelative(org.bukkit.block.BlockFace.EAST);
+                    } else if (movement.x < vec3.x) {
+                        bl = bl.getRelative(org.bukkit.block.BlockFace.WEST);
+                    } else if (movement.z > vec3.z) {
+                        bl = bl.getRelative(org.bukkit.block.BlockFace.SOUTH);
+                    } else if (movement.z < vec3.z) {
+                        bl = bl.getRelative(org.bukkit.block.BlockFace.NORTH);
+                    }
+
+                    if (!bl.getType().isAir()) {
+                        org.bukkit.event.vehicle.VehicleBlockCollisionEvent event = new org.bukkit.event.vehicle.VehicleBlockCollisionEvent(vehicle, bl, org.bukkit.craftbukkit.util.CraftVector.toBukkit(originalMovement)); // Paper - Expose pre-collision velocity
+                        this.level.getCraftServer().getPluginManager().callEvent(event);
+                    }
+                }
+                // CraftBukkit end
+
                 if (!this.level().isClientSide() || this.isControlledByLocalInstance()) {
                     Entity.MovementEmission movementEmission = this.getMovementEmission();
                     if (movementEmission.emitsAnything() && !this.isPassenger()) {
@@ -850,7 +_,7 @@
     }
 
     protected BlockPos getOnPos(float yOffset) {
-        if (this.mainSupportingBlockPos.isPresent()) {
+        if (this.mainSupportingBlockPos.isPresent() && this.level().getChunkIfLoadedImmediately(this.mainSupportingBlockPos.get()) != null) { // Paper - ensure no loads
             BlockPos blockPos = this.mainSupportingBlockPos.get();
             if (!(yOffset > 1.0E-5F)) {
                 return blockPos;
@@ -1049,6 +_,20 @@
         return SoundEvents.GENERIC_SPLASH;
     }
 
+    // CraftBukkit start - Add delegate methods
+    public SoundEvent getSwimSound0() {
+        return this.getSwimSound();
+    }
+
+    public SoundEvent getSwimSplashSound0() {
+        return this.getSwimSplashSound();
+    }
+
+    public SoundEvent getSwimHighSpeedSplashSound0() {
+        return this.getSwimHighSpeedSplashSound();
+    }
+    // CraftBukkit end
+
     public void recordMovementThroughBlocks(Vec3 oldPosition, Vec3 position) {
         this.movementThisTick.add(new Entity.Movement(oldPosition, position));
     }
@@ -1485,6 +_,7 @@
         this.setXRot(Mth.clamp(xRot, -90.0F, 90.0F) % 360.0F);
         this.yRotO = this.getYRot();
         this.xRotO = this.getXRot();
+        this.setYHeadRot(yRot); // Paper - Update head rotation
     }
 
     public void absMoveTo(double x, double y, double z) {
@@ -1494,6 +_,7 @@
         this.yo = y;
         this.zo = d1;
         this.setPos(d, y, d1);
+        if (this.valid) this.level.getChunk((int) Math.floor(this.getX()) >> 4, (int) Math.floor(this.getZ()) >> 4); // CraftBukkit
     }
 
     public void moveTo(Vec3 vec) {
@@ -1513,11 +_,19 @@
     }
 
     public void moveTo(double x, double y, double z, float yRot, float xRot) {
+        // Paper start - Fix Entity Teleportation and cancel velocity if teleported
+        if (!preserveMotion) {
+            this.deltaMovement = Vec3.ZERO;
+        } else {
+            this.preserveMotion = false;
+        }
+        // Paper end - Fix Entity Teleportation and cancel velocity if teleported
         this.setPosRaw(x, y, z);
         this.setYRot(yRot);
         this.setXRot(xRot);
         this.setOldPosAndRot();
         this.reapplyPosition();
+        this.setYHeadRot(yRot); // Paper - Update head rotation
     }
 
     public final void setOldPosAndRot() {
@@ -1584,6 +_,7 @@
     public void push(Entity entity) {
         if (!this.isPassengerOfSameVehicle(entity)) {
             if (!entity.noPhysics && !this.noPhysics) {
+                if (this.level.paperConfig().collisions.onlyPlayersCollide && !(entity instanceof ServerPlayer || this instanceof ServerPlayer)) return; // Paper - Collision option for requiring a player participant
                 double d = entity.getX() - this.getX();
                 double d1 = entity.getZ() - this.getZ();
                 double max = Mth.absMax(d, d1);
@@ -1617,7 +_,21 @@
     }
 
     public void push(double x, double y, double z) {
-        this.setDeltaMovement(this.getDeltaMovement().add(x, y, z));
+        // Paper start - Add EntityKnockbackByEntityEvent and EntityPushedByEntityAttackEvent
+        this.push(x, y, z, null);
+    }
+
+    public void push(double x, double y, double z, @Nullable Entity pushingEntity) {
+        org.bukkit.util.Vector delta = new org.bukkit.util.Vector(x, y, z);
+        if (pushingEntity != null) {
+            io.papermc.paper.event.entity.EntityPushedByEntityAttackEvent event = new io.papermc.paper.event.entity.EntityPushedByEntityAttackEvent(this.getBukkitEntity(), io.papermc.paper.event.entity.EntityKnockbackEvent.Cause.PUSH, pushingEntity.getBukkitEntity(), delta);
+            if (!event.callEvent()) {
+                return;
+            }
+            delta = event.getKnockback();
+        }
+        this.setDeltaMovement(this.getDeltaMovement().add(delta.getX(), delta.getY(), delta.getZ()));
+        // Paper end - Add EntityKnockbackByEntityEvent and EntityPushedByEntityAttackEvent
         this.hasImpulse = true;
     }
 
@@ -1724,8 +_,20 @@
     }
 
     public boolean isPushable() {
+        // Paper start - Climbing should not bypass cramming gamerule
+        return isCollidable(false);
+    }
+
+    public boolean isCollidable(boolean ignoreClimbing) {
+        // Paper end - Climbing should not bypass cramming gamerule
         return false;
     }
+
+    // CraftBukkit start - collidable API
+    public boolean canCollideWithBukkit(Entity entity) {
+        return this.isPushable();
+    }
+    // CraftBukkit end
 
     public void awardKillScore(Entity entity, DamageSource damageSource) {
         if (entity instanceof ServerPlayer) {
@@ -1752,34 +_,70 @@
     }
 
     public boolean saveAsPassenger(CompoundTag compound) {
+        // CraftBukkit start - allow excluding certain data when saving
+        return this.saveAsPassenger(compound, true);
+    }
+
+    public boolean saveAsPassenger(CompoundTag compound, boolean includeAll) {
+        // CraftBukkit end
         if (this.removalReason != null && !this.removalReason.shouldSave()) {
             return false;
         } else {
             String encodeId = this.getEncodeId();
-            if (encodeId == null) {
+            if (!this.persist || encodeId == null) { // CraftBukkit - persist flag
                 return false;
             } else {
                 compound.putString("id", encodeId);
-                this.saveWithoutId(compound);
+                this.saveWithoutId(compound, includeAll); // CraftBukkit - pass on includeAll
                 return true;
             }
         }
     }
+
+    // Paper start - Entity serialization api
+    public boolean serializeEntity(CompoundTag compound) {
+        List<Entity> pass = new java.util.ArrayList<>(this.getPassengers());
+        this.passengers = ImmutableList.of();
+        boolean result = save(compound);
+        this.passengers = ImmutableList.copyOf(pass);
+        return result;
+    }
+    // Paper end - Entity serialization api
 
     public boolean save(CompoundTag compound) {
         return !this.isPassenger() && this.saveAsPassenger(compound);
     }
 
     public CompoundTag saveWithoutId(CompoundTag compound) {
+        // CraftBukkit start - allow excluding certain data when saving
+        return this.saveWithoutId(compound, true);
+    }
+
+    public CompoundTag saveWithoutId(CompoundTag compound, boolean includeAll) {
+        // CraftBukkit end
         try {
-            if (this.vehicle != null) {
-                compound.put("Pos", this.newDoubleList(this.vehicle.getX(), this.getY(), this.vehicle.getZ()));
-            } else {
-                compound.put("Pos", this.newDoubleList(this.getX(), this.getY(), this.getZ()));
-            }
+            // CraftBukkit start - selectively save position
+            if (includeAll) {
+                if (this.vehicle != null) {
+                    compound.put("Pos", this.newDoubleList(this.vehicle.getX(), this.getY(), this.vehicle.getZ()));
+                } else {
+                    compound.put("Pos", this.newDoubleList(this.getX(), this.getY(), this.getZ()));
+                }
+             }
+            // CraftBukkit end
 
             Vec3 deltaMovement = this.getDeltaMovement();
             compound.put("Motion", this.newDoubleList(deltaMovement.x, deltaMovement.y, deltaMovement.z));
+            // CraftBukkit start - Checking for NaN pitch/yaw and resetting to zero
+            // TODO: make sure this is the best way to address this.
+            if (Float.isNaN(this.yRot)) {
+                this.yRot = 0;
+            }
+
+            if (Float.isNaN(this.xRot)) {
+                this.xRot = 0;
+            }
+            // CraftBukkit end
             compound.put("Rotation", this.newFloatList(this.getYRot(), this.getXRot()));
             compound.putFloat("FallDistance", this.fallDistance);
             compound.putShort("Fire", (short)this.remainingFireTicks);
@@ -1787,7 +_,29 @@
             compound.putBoolean("OnGround", this.onGround());
             compound.putBoolean("Invulnerable", this.invulnerable);
             compound.putInt("PortalCooldown", this.portalCooldown);
-            compound.putUUID("UUID", this.getUUID());
+            // CraftBukkit start - selectively save uuid and world
+            if (includeAll) {
+                compound.putUUID("UUID", this.getUUID());
+                // PAIL: Check above UUID reads 1.8 properly, ie: UUIDMost / UUIDLeast
+                compound.putLong("WorldUUIDLeast", this.level.getWorld().getUID().getLeastSignificantBits());
+                compound.putLong("WorldUUIDMost", this.level.getWorld().getUID().getMostSignificantBits());
+            }
+            compound.putInt("Bukkit.updateLevel", Entity.CURRENT_LEVEL);
+            if (!this.persist) {
+                compound.putBoolean("Bukkit.persist", this.persist);
+            }
+            if (!this.visibleByDefault) {
+                compound.putBoolean("Bukkit.visibleByDefault", this.visibleByDefault);
+            }
+            if (this.persistentInvisibility) {
+                compound.putBoolean("Bukkit.invisible", this.persistentInvisibility);
+            }
+            // SPIGOT-6907: re-implement LivingEntity#setMaximumAir()
+            if (this.maxAirTicks != this.getDefaultMaxAirSupply()) {
+                compound.putInt("Bukkit.MaxAirSupply", this.getMaxAirSupply());
+            }
+            compound.putInt("Spigot.ticksLived", this.tickCount);
+            // CraftBukkit end
             Component customName = this.getCustomName();
             if (customName != null) {
                 compound.putString("CustomName", Component.Serializer.toJson(customName, this.registryAccess()));
@@ -1828,13 +_,13 @@
                 compound.put("Tags", listTag);
             }
 
-            this.addAdditionalSaveData(compound);
+            this.addAdditionalSaveData(compound, includeAll); // CraftBukkit - pass on includeAll
             if (this.isVehicle()) {
                 ListTag listTag = new ListTag();
 
                 for (Entity entity : this.getPassengers()) {
                     CompoundTag compoundTag = new CompoundTag();
-                    if (entity.saveAsPassenger(compoundTag)) {
+                    if (entity.saveAsPassenger(compoundTag, includeAll)) { // CraftBukkit - pass on includeAll
                         listTag.add(compoundTag);
                     }
                 }
@@ -1844,6 +_,33 @@
                 }
             }
 
+            // CraftBukkit start - stores eventually existing bukkit values
+            if (this.bukkitEntity != null) {
+                this.bukkitEntity.storeBukkitValues(compound);
+            }
+            // CraftBukkit end
+            // Paper start
+            if (this.origin != null) {
+                UUID originWorld = this.originWorld != null ? this.originWorld : this.level != null ? this.level.getWorld().getUID() : null;
+                if (originWorld != null) {
+                    compound.putUUID("Paper.OriginWorld", originWorld);
+                }
+                compound.put("Paper.Origin", this.newDoubleList(this.origin.getX(), this.origin.getY(), this.origin.getZ()));
+            }
+            if (this.spawnReason != null) {
+                compound.putString("Paper.SpawnReason", this.spawnReason.name());
+            }
+            // Save entity's from mob spawner status
+            if (this.spawnedViaMobSpawner) {
+                compound.putBoolean("Paper.FromMobSpawner", true);
+            }
+            if (this.fromNetherPortal) {
+                compound.putBoolean("Paper.FromNetherPortal", true);
+            }
+            if (this.freezeLocked) {
+                compound.putBoolean("Paper.FreezeLock", true);
+            }
+            // Paper end
             return compound;
         } catch (Throwable var9) {
             CrashReport crashReport = CrashReport.forThrowable(var9, "Saving entity NBT");
@@ -1930,6 +_,69 @@
             } else {
                 throw new IllegalStateException("Entity has invalid rotation");
             }
+            // CraftBukkit start
+            // Spigot start
+            if (this instanceof net.minecraft.world.entity.LivingEntity) {
+                this.tickCount = compound.getInt("Spigot.ticksLived");
+            }
+            // Spigot end
+            this.persist = !compound.contains("Bukkit.persist") || compound.getBoolean("Bukkit.persist");
+            this.visibleByDefault = !compound.contains("Bukkit.visibleByDefault") || compound.getBoolean("Bukkit.visibleByDefault");
+            // SPIGOT-6907: re-implement LivingEntity#setMaximumAir()
+            if (compound.contains("Bukkit.MaxAirSupply")) {
+                this.maxAirTicks = compound.getInt("Bukkit.MaxAirSupply");
+            }
+            // CraftBukkit end
+
+            // CraftBukkit start
+            // Paper - move world parsing/loading to PlayerList#placeNewPlayer
+            this.getBukkitEntity().readBukkitValues(compound);
+            if (compound.contains("Bukkit.invisible")) {
+                boolean bukkitInvisible = compound.getBoolean("Bukkit.invisible");
+                this.setInvisible(bukkitInvisible);
+                this.persistentInvisibility = bukkitInvisible;
+            }
+            // CraftBukkit end
+
+            // Paper start
+            ListTag originTag = compound.getList("Paper.Origin", net.minecraft.nbt.Tag.TAG_DOUBLE);
+            if (!originTag.isEmpty()) {
+                UUID originWorld = null;
+                if (compound.contains("Paper.OriginWorld")) {
+                    originWorld = compound.getUUID("Paper.OriginWorld");
+                } else if (this.level != null) {
+                    originWorld = this.level.getWorld().getUID();
+                }
+                this.originWorld = originWorld;
+                origin = new org.bukkit.util.Vector(originTag.getDouble(0), originTag.getDouble(1), originTag.getDouble(2));
+            }
+
+            spawnedViaMobSpawner = compound.getBoolean("Paper.FromMobSpawner"); // Restore entity's from mob spawner status
+            fromNetherPortal = compound.getBoolean("Paper.FromNetherPortal");
+            if (compound.contains("Paper.SpawnReason")) {
+                String spawnReasonName = compound.getString("Paper.SpawnReason");
+                try {
+                    spawnReason = org.bukkit.event.entity.CreatureSpawnEvent.SpawnReason.valueOf(spawnReasonName);
+                } catch (Exception ignored) {
+                    LOGGER.error("Unknown SpawnReason " + spawnReasonName + " for " + this);
+                }
+            }
+            if (spawnReason == null) {
+                if (spawnedViaMobSpawner) {
+                    spawnReason = org.bukkit.event.entity.CreatureSpawnEvent.SpawnReason.SPAWNER;
+                } else if (this instanceof Mob && (this instanceof net.minecraft.world.entity.animal.Animal || this instanceof net.minecraft.world.entity.animal.AbstractFish) && !((Mob) this).removeWhenFarAway(0.0)) {
+                    if (!compound.getBoolean("PersistenceRequired")) {
+                        spawnReason = org.bukkit.event.entity.CreatureSpawnEvent.SpawnReason.NATURAL;
+                    }
+                }
+            }
+            if (spawnReason == null) {
+                spawnReason = org.bukkit.event.entity.CreatureSpawnEvent.SpawnReason.DEFAULT;
+            }
+            if (compound.contains("Paper.FreezeLock")) {
+                freezeLocked = compound.getBoolean("Paper.FreezeLock");
+            }
+            // Paper end
         } catch (Throwable var17) {
             CrashReport crashReport = CrashReport.forThrowable(var17, "Loading entity NBT");
             CrashReportCategory crashReportCategory = crashReport.addCategory("Entity being loaded");
@@ -1949,6 +_,12 @@
         return type.canSerialize() && key != null ? key.toString() : null;
     }
 
+    // CraftBukkit start - allow excluding certain data when saving
+    protected void addAdditionalSaveData(CompoundTag tag, boolean includeAll) {
+        this.addAdditionalSaveData(tag);
+    }
+    // CraftBukkit end
+
     protected abstract void readAdditionalSaveData(CompoundTag tag);
 
     protected abstract void addAdditionalSaveData(CompoundTag tag);
@@ -1990,11 +_,61 @@
 
     @Nullable
     public ItemEntity spawnAtLocation(ServerLevel level, ItemStack stack, float yOffset) {
+        // Paper start - Restore vanilla drops behavior
+        return this.spawnAtLocation(level, stack, yOffset, null);
+    }
+    public record DefaultDrop(Item item, org.bukkit.inventory.ItemStack stack, @Nullable java.util.function.Consumer<ItemStack> dropConsumer) {
+        public DefaultDrop(final ItemStack stack, final java.util.function.Consumer<ItemStack> dropConsumer) {
+            this(stack.getItem(), org.bukkit.craftbukkit.inventory.CraftItemStack.asCraftMirror(stack), dropConsumer);
+        }
+
+        public void runConsumer(final java.util.function.Consumer<org.bukkit.inventory.ItemStack> fallback) {
+            if (this.dropConsumer == null || org.bukkit.craftbukkit.inventory.CraftItemType.bukkitToMinecraft(this.stack.getType()) != this.item) {
+                fallback.accept(this.stack);
+            } else {
+                this.dropConsumer.accept(org.bukkit.craftbukkit.inventory.CraftItemStack.asNMSCopy(this.stack));
+            }
+        }
+    }
+    @Nullable
+    public ItemEntity spawnAtLocation(ServerLevel level, ItemStack stack, float yOffset, @Nullable java.util.function.Consumer<? super ItemEntity> delayedAddConsumer) {
+        // Paper end - Restore vanilla drops behavior
         if (stack.isEmpty()) {
             return null;
         } else {
-            ItemEntity itemEntity = new ItemEntity(level, this.getX(), this.getY() + yOffset, this.getZ(), stack);
+            // CraftBukkit start - Capture drops for death event
+            if (this instanceof net.minecraft.world.entity.LivingEntity && !this.forceDrops) {
+                // Paper start - Restore vanilla drops behavior
+                ((net.minecraft.world.entity.LivingEntity) this).drops.add(new net.minecraft.world.entity.Entity.DefaultDrop(stack, itemStack -> {
+                    ItemEntity itemEntity = new ItemEntity(this.level, this.getX(), this.getY() + (double) yOffset, this.getZ(), itemStack); // stack is copied before consumer
+                    itemEntity.setDefaultPickUpDelay();
+                    this.level.addFreshEntity(itemEntity);
+                    if (delayedAddConsumer != null) delayedAddConsumer.accept(itemEntity);
+                }));
+                // Paper end - Restore vanilla drops behavior
+                return null;
+            }
+            // CraftBukkit end
+            ItemEntity itemEntity = new ItemEntity(level, this.getX(), this.getY() + yOffset, this.getZ(), stack.copy()); // Paper - copy so we can destroy original
+            stack.setCount(0); // Paper - destroy this item - if this ever leaks due to game bugs, ensure it doesn't dupe
+
             itemEntity.setDefaultPickUpDelay();
+            itemEntity.setDefaultPickUpDelay(); // Paper - diff on change (in dropConsumer)
+            // Paper start - Call EntityDropItemEvent
+            return this.spawnAtLocation(level, itemEntity);
+        }
+    }
+    @Nullable
+    public ItemEntity spawnAtLocation(ServerLevel level, ItemEntity itemEntity) {
+        {
+            // Paper end - Call EntityDropItemEvent
+            // CraftBukkit start
+            org.bukkit.event.entity.EntityDropItemEvent event = new org.bukkit.event.entity.EntityDropItemEvent(this.getBukkitEntity(), (org.bukkit.entity.Item) itemEntity.getBukkitEntity());
+            org.bukkit.Bukkit.getPluginManager().callEvent(event);
+            if (event.isCancelled()) {
+                return null;
+            }
+            // CraftBukkit end
             level.addFreshEntity(itemEntity);
             return itemEntity;
         }
@@ -2028,7 +_,16 @@
         if (this.isAlive() && this instanceof Leashable leashable) {
             if (leashable.getLeashHolder() == player) {
                 if (!this.level().isClientSide()) {
-                    if (player.hasInfiniteMaterials()) {
+                    // CraftBukkit start - fire PlayerUnleashEntityEvent
+                    // Paper start - Expand EntityUnleashEvent
+                    org.bukkit.event.player.PlayerUnleashEntityEvent event = org.bukkit.craftbukkit.event.CraftEventFactory.callPlayerUnleashEntityEvent(this, player, hand, !player.hasInfiniteMaterials());
+                    if (event.isCancelled()) {
+                        // Paper end - Expand EntityUnleashEvent
+                        ((ServerPlayer) player).connection.send(new net.minecraft.network.protocol.game.ClientboundSetEntityLinkPacket(this, leashable.getLeashHolder()));
+                        return InteractionResult.PASS;
+                    }
+                    // CraftBukkit end
+                    if (!event.isDropLeash()) { // Paper - Expand EntityUnleashEvent
                         leashable.removeLeash();
                     } else {
                         leashable.dropLeash();
@@ -2043,6 +_,13 @@
             ItemStack itemInHand = player.getItemInHand(hand);
             if (itemInHand.is(Items.LEAD) && leashable.canHaveALeashAttachedToIt()) {
                 if (!this.level().isClientSide()) {
+                    // CraftBukkit start - fire PlayerLeashEntityEvent
+                    if (org.bukkit.craftbukkit.event.CraftEventFactory.callPlayerLeashEntityEvent(this, player, player, hand).isCancelled()) {
+                        ((ServerPlayer) player).connection.send(new net.minecraft.network.protocol.game.ClientboundSetEntityLinkPacket(this, leashable.getLeashHolder()));
+                        player.containerMenu.sendAllDataToRemote(); // Paper - Fix inventory desync
+                        return InteractionResult.PASS;
+                    }
+                    // CraftBukkit end
                     leashable.setLeashedTo(player, true);
                 }
 
@@ -2116,11 +_,11 @@
     }
 
     public boolean startRiding(Entity vehicle, boolean force) {
-        if (vehicle == this.vehicle) {
+        if (vehicle == this.vehicle || vehicle.level != this.level) { // Paper - Ensure entity passenger world matches ridden entity (bad plugins)
             return false;
         } else if (!vehicle.couldAcceptPassenger()) {
             return false;
-        } else if (!this.level().isClientSide() && !vehicle.type.canSerialize()) {
+        } else if (!force && !this.level().isClientSide() && !vehicle.type.canSerialize()) { // SPIGOT-7947: Allow force riding all entities
             return false;
         } else {
             for (Entity entity = vehicle; entity.vehicle != null; entity = entity.vehicle) {
@@ -2130,6 +_,27 @@
             }
 
             if (force || this.canRide(vehicle) && vehicle.canAddPassenger(this)) {
+                // CraftBukkit start
+                if (vehicle.getBukkitEntity() instanceof org.bukkit.entity.Vehicle && this.getBukkitEntity() instanceof org.bukkit.entity.LivingEntity) {
+                    org.bukkit.event.vehicle.VehicleEnterEvent event = new org.bukkit.event.vehicle.VehicleEnterEvent((org.bukkit.entity.Vehicle) vehicle.getBukkitEntity(), this.getBukkitEntity());
+                    // Suppress during worldgen
+                    if (this.valid) {
+                        org.bukkit.Bukkit.getPluginManager().callEvent(event);
+                    }
+                    if (event.isCancelled()) {
+                        return false;
+                    }
+                }
+
+                org.bukkit.event.entity.EntityMountEvent event = new org.bukkit.event.entity.EntityMountEvent(this.getBukkitEntity(), vehicle.getBukkitEntity());
+                // Suppress during worldgen
+                if (this.valid) {
+                    org.bukkit.Bukkit.getPluginManager().callEvent(event);
+                }
+                if (event.isCancelled()) {
+                    return false;
+                }
+                // CraftBukkit end
                 if (this.isPassenger()) {
                     this.stopRiding();
                 }
@@ -2158,15 +_,26 @@
     }
 
     public void removeVehicle() {
+        // Paper start - Force entity dismount during teleportation
+        this.removeVehicle(false);
+    }
+    public void removeVehicle(boolean suppressCancellation) {
+        // Paper end - Force entity dismount during teleportation
         if (this.vehicle != null) {
             Entity entity = this.vehicle;
             this.vehicle = null;
-            entity.removePassenger(this);
+            if (!entity.removePassenger(this, suppressCancellation)) this.vehicle = entity; // CraftBukkit // Paper - Force entity dismount during teleportation
         }
     }
 
     public void stopRiding() {
-        this.removeVehicle();
+        // Paper start - Force entity dismount during teleportation
+        this.stopRiding(false);
+    }
+
+    public void stopRiding(boolean suppressCancellation) {
+        this.removeVehicle(suppressCancellation);
+        // Paper end - Force entity dismount during teleportation
     }
 
     protected void addPassenger(Entity passenger) {
@@ -2190,10 +_,43 @@
         }
     }
 
-    protected void removePassenger(Entity passenger) {
+    // Paper start - Force entity dismount during teleportation
+    protected boolean removePassenger(Entity passenger) {
+        return removePassenger(passenger, false);
+    }
+    protected boolean removePassenger(Entity passenger, boolean suppressCancellation) { // CraftBukkit
+        // Paper end - Force entity dismount during teleportation
         if (passenger.getVehicle() == this) {
             throw new IllegalStateException("Use x.stopRiding(y), not y.removePassenger(x)");
         } else {
+            // CraftBukkit start
+            org.bukkit.craftbukkit.entity.CraftEntity craft = (org.bukkit.craftbukkit.entity.CraftEntity) passenger.getBukkitEntity().getVehicle();
+            Entity orig = craft == null ? null : craft.getHandle();
+            if (this.getBukkitEntity() instanceof org.bukkit.entity.Vehicle && passenger.getBukkitEntity() instanceof org.bukkit.entity.LivingEntity) {
+                org.bukkit.event.vehicle.VehicleExitEvent event = new org.bukkit.event.vehicle.VehicleExitEvent(
+                        (org.bukkit.entity.Vehicle) this.getBukkitEntity(),
+                        (org.bukkit.entity.LivingEntity) passenger.getBukkitEntity(), !suppressCancellation // Paper - Force entity dismount during teleportation
+                );
+                // Suppress during worldgen
+                if (this.valid) {
+                    org.bukkit.Bukkit.getPluginManager().callEvent(event);
+                }
+                org.bukkit.craftbukkit.entity.CraftEntity craftn = (org.bukkit.craftbukkit.entity.CraftEntity) passenger.getBukkitEntity().getVehicle();
+                Entity n = craftn == null ? null : craftn.getHandle();
+                if (event.isCancelled() || n != orig) {
+                    return false;
+                }
+            }
+
+            org.bukkit.event.entity.EntityDismountEvent event = new org.bukkit.event.entity.EntityDismountEvent(passenger.getBukkitEntity(), this.getBukkitEntity(), !suppressCancellation); // Paper - Force entity dismount during teleportation
+            // Suppress during worldgen
+            if (this.valid) {
+                org.bukkit.Bukkit.getPluginManager().callEvent(event);
+            }
+            if (event.isCancelled()) {
+                return false;
+            }
+            // CraftBukkit end
             if (this.passengers.size() == 1 && this.passengers.get(0) == passenger) {
                 this.passengers = ImmutableList.of();
             } else {
@@ -2203,6 +_,7 @@
             passenger.boardingCooldown = 60;
             this.gameEvent(GameEvent.ENTITY_DISMOUNT, passenger);
         }
+        return true; // CraftBukkit
     }
 
     protected boolean canAddPassenger(Entity passenger) {
@@ -2295,8 +_,8 @@
                     TeleportTransition portalDestination = this.portalProcess.getPortalDestination(serverLevel, this);
                     if (portalDestination != null) {
                         ServerLevel level = portalDestination.newLevel();
-                        if (serverLevel.getServer().isLevelEnabled(level)
-                            && (level.dimension() == serverLevel.dimension() || this.canTeleport(serverLevel, level))) {
+                        if (this instanceof ServerPlayer // CraftBukkit - always call event for players
+                            || (level != null && (level.dimension() == serverLevel.dimension() || this.canTeleport(serverLevel, level)))) { // CraftBukkit
                             this.teleport(portalDestination);
                         }
                     }
@@ -2377,7 +_,7 @@
     }
 
     public boolean isCrouching() {
-        return this.hasPose(Pose.CROUCHING);
+        return this.hasPose(net.minecraft.world.entity.Pose.CROUCHING);
     }
 
     public boolean isSprinting() {
@@ -2393,7 +_,7 @@
     }
 
     public boolean isVisuallySwimming() {
-        return this.hasPose(Pose.SWIMMING);
+        return this.hasPose(net.minecraft.world.entity.Pose.SWIMMING);
     }
 
     public boolean isVisuallyCrawling() {
@@ -2401,6 +_,13 @@
     }
 
     public void setSwimming(boolean swimming) {
+        // CraftBukkit start
+        if (this.valid && this.isSwimming() != swimming && this instanceof net.minecraft.world.entity.LivingEntity) {
+            if (org.bukkit.craftbukkit.event.CraftEventFactory.callToggleSwimEvent((net.minecraft.world.entity.LivingEntity) this, swimming).isCancelled()) {
+                return;
+            }
+        }
+        // CraftBukkit end
         this.setSharedFlag(4, swimming);
     }
 
@@ -2439,6 +_,7 @@
 
     @Nullable
     public PlayerTeam getTeam() {
+        if (!this.level().paperConfig().scoreboards.allowNonPlayerEntitiesOnScoreboards && !(this instanceof Player)) { return null; } // Paper - Perf: Disable Scoreboards for non players by default
         return this.level().getScoreboard().getPlayersTeam(this.getScoreboardName());
     }
 
@@ -2455,7 +_,11 @@
     }
 
     public void setInvisible(boolean invisible) {
-        this.setSharedFlag(5, invisible);
+        // CraftBukkit - start
+        if (!this.persistentInvisibility) { // Prevent Minecraft from removing our invisibility flag
+            this.setSharedFlag(5, invisible);
+        }
+        // CraftBukkit - end
     }
 
     public boolean getSharedFlag(int flag) {
@@ -2472,7 +_,7 @@
     }
 
     public int getMaxAirSupply() {
-        return 300;
+        return this.maxAirTicks; // CraftBukkit - SPIGOT-6907: re-implement LivingEntity#setMaximumAir()
     }
 
     public int getAirSupply() {
@@ -2480,7 +_,18 @@
     }
 
     public void setAirSupply(int air) {
-        this.entityData.set(DATA_AIR_SUPPLY_ID, air);
+        // CraftBukkit start
+        org.bukkit.event.entity.EntityAirChangeEvent event = new org.bukkit.event.entity.EntityAirChangeEvent(this.getBukkitEntity(), air);
+        // Suppress during worldgen
+        if (this.valid) {
+            event.getEntity().getServer().getPluginManager().callEvent(event);
+        }
+        if (event.isCancelled() && this.getAirSupply() != air) {
+            this.entityData.markDirty(Entity.DATA_AIR_SUPPLY_ID);
+            return;
+        }
+        this.entityData.set(Entity.DATA_AIR_SUPPLY_ID, event.getAmount());
+        // CraftBukkit end
     }
 
     public int getTicksFrozen() {
@@ -2506,11 +_,43 @@
 
     public void thunderHit(ServerLevel level, LightningBolt lightning) {
         this.setRemainingFireTicks(this.remainingFireTicks + 1);
+        // CraftBukkit start
+        final org.bukkit.entity.Entity thisBukkitEntity = this.getBukkitEntity();
+        final org.bukkit.entity.Entity stormBukkitEntity = lightning.getBukkitEntity();
+        final org.bukkit.plugin.PluginManager pluginManager = org.bukkit.Bukkit.getPluginManager();
+        // CraftBukkit end
         if (this.remainingFireTicks == 0) {
-            this.igniteForSeconds(8.0F);
-        }
-
-        this.hurtServer(level, this.damageSources().lightningBolt(), 5.0F);
+            // CraftBukkit start - Call a combust event when lightning strikes
+            org.bukkit.event.entity.EntityCombustByEntityEvent entityCombustEvent = new org.bukkit.event.entity.EntityCombustByEntityEvent(stormBukkitEntity, thisBukkitEntity, 8.0F);
+            pluginManager.callEvent(entityCombustEvent);
+            if (!entityCombustEvent.isCancelled()) {
+                this.igniteForSeconds(entityCombustEvent.getDuration(), false);
+            // Paper start - fix EntityCombustEvent cancellation
+            } else {
+                this.setRemainingFireTicks(this.remainingFireTicks - 1);
+            // Paper end - fix EntityCombustEvent cancellation
+            }
+            // CraftBukkit end
+        }
+
+        // CraftBukkit start
+        if (thisBukkitEntity instanceof org.bukkit.entity.Hanging) {
+            org.bukkit.event.hanging.HangingBreakByEntityEvent hangingEvent = new org.bukkit.event.hanging.HangingBreakByEntityEvent((org.bukkit.entity.Hanging) thisBukkitEntity, stormBukkitEntity);
+            pluginManager.callEvent(hangingEvent);
+
+            if (hangingEvent.isCancelled()) {
+                return;
+            }
+        }
+
+        if (this.fireImmune()) {
+            return;
+        }
+
+        if (!this.hurtServer(level, this.damageSources().lightningBolt().customEventDamager(lightning), 5.0F)) { // Paper - fix DamageSource API
+            return;
+        }
+        // CraftBukkit end
     }
 
     public void onAboveBubbleCol(boolean downwards) {
@@ -2636,26 +_,30 @@
         return this.removalReason != null
             ? String.format(
                 Locale.ROOT,
-                "%s['%s'/%d, l='%s', x=%.2f, y=%.2f, z=%.2f, removed=%s]",
+                "%s['%s'/%d, uuid='%s', l='%s', x=%.2f, y=%.2f, z=%.2f, cpos=%s, tl=%d, v=%b, removed=%s]", // Paper - add more info
                 this.getClass().getSimpleName(),
                 this.getName().getString(),
                 this.id,
+                this.uuid, // Paper - add more info
                 string,
                 this.getX(),
                 this.getY(),
                 this.getZ(),
+                this.chunkPosition(), this.tickCount, this.valid, // Paper - add more info
                 this.removalReason
             )
             : String.format(
                 Locale.ROOT,
-                "%s['%s'/%d, l='%s', x=%.2f, y=%.2f, z=%.2f]",
+                "%s['%s'/%d, uuid='%s', l='%s', x=%.2f, y=%.2f, z=%.2f, cpos=%s, tl=%d, v=%b]", // Paper - add more info
                 this.getClass().getSimpleName(),
                 this.getName().getString(),
                 this.id,
+                this.uuid, // Paper - add more info
                 string,
                 this.getX(),
                 this.getY(),
-                this.getZ()
+                this.getZ(),
+                this.chunkPosition(), this.tickCount, this.valid // Paper - add more info
             );
     }
 
@@ -2679,6 +_,13 @@
     }
 
     public void restoreFrom(Entity entity) {
+        // Paper start - Forward CraftEntity in teleport command
+        org.bukkit.craftbukkit.entity.CraftEntity bukkitEntity = entity.bukkitEntity;
+        if (bukkitEntity != null) {
+            bukkitEntity.setHandle(this);
+            this.bukkitEntity = bukkitEntity;
+        }
+        // Paper end - Forward CraftEntity in teleport command
         CompoundTag compoundTag = entity.saveWithoutId(new CompoundTag());
         compoundTag.remove("Dimension");
         this.load(compoundTag);
@@ -2688,7 +_,56 @@
 
     @Nullable
     public Entity teleport(TeleportTransition teleportTransition) {
+        // Paper start - Fix item duplication and teleport issues
+        if ((!this.isAlive() || !this.valid) && (teleportTransition.newLevel() != this.level)) {
+            LOGGER.warn("Illegal Entity Teleport " + this + " to " + teleportTransition.newLevel() + ":" + teleportTransition.position(), new Throwable());
+            return null;
+        }
+        // Paper end - Fix item duplication and teleport issues
         if (this.level() instanceof ServerLevel serverLevel && !this.isRemoved()) {
+            // CraftBukkit start
+            PositionMoveRotation absolutePosition = PositionMoveRotation.calculateAbsolute(PositionMoveRotation.of(this), PositionMoveRotation.of(teleportTransition), teleportTransition.relatives());
+            Vec3 velocity = absolutePosition.deltaMovement(); // Paper
+            org.bukkit.Location to = org.bukkit.craftbukkit.util.CraftLocation.toBukkit(absolutePosition.position(), teleportTransition.newLevel().getWorld(), absolutePosition.yRot(), absolutePosition.xRot());
+            // Paper start - gateway-specific teleport event
+            final org.bukkit.event.entity.EntityTeleportEvent teleEvent;
+            if (this.portalProcess != null && this.portalProcess.isSamePortal(((net.minecraft.world.level.block.EndGatewayBlock) net.minecraft.world.level.block.Blocks.END_GATEWAY)) && this.level.getBlockEntity(this.portalProcess.getEntryPosition()) instanceof net.minecraft.world.level.block.entity.TheEndGatewayBlockEntity theEndGatewayBlockEntity) {
+                teleEvent = new com.destroystokyo.paper.event.entity.EntityTeleportEndGatewayEvent(this.getBukkitEntity(), this.getBukkitEntity().getLocation(), to, new org.bukkit.craftbukkit.block.CraftEndGateway(to.getWorld(), theEndGatewayBlockEntity));
+                teleEvent.callEvent();
+            } else {
+                teleEvent = org.bukkit.craftbukkit.event.CraftEventFactory.callEntityTeleportEvent(this, to);
+            }
+            // Paper end - gateway-specific teleport event
+            if (teleEvent.isCancelled() || teleEvent.getTo() == null) {
+                return null;
+            }
+            if (!to.equals(teleEvent.getTo())) {
+                to = teleEvent.getTo();
+                teleportTransition = new TeleportTransition(((org.bukkit.craftbukkit.CraftWorld) to.getWorld()).getHandle(), org.bukkit.craftbukkit.util.CraftLocation.toVec3D(to), Vec3.ZERO, to.getYaw(), to.getPitch(), teleportTransition.missingRespawnBlock(), teleportTransition.asPassenger(), Set.of(), teleportTransition.postTeleportTransition(), teleportTransition.cause());
+                // Paper start - Call EntityPortalExitEvent
+                velocity = Vec3.ZERO;
+            }
+            if (this.portalProcess != null) { // if in a portal
+                org.bukkit.craftbukkit.entity.CraftEntity bukkitEntity = this.getBukkitEntity();
+                org.bukkit.event.entity.EntityPortalExitEvent event = new org.bukkit.event.entity.EntityPortalExitEvent(
+                    bukkitEntity,
+                    bukkitEntity.getLocation(), to.clone(),
+                    bukkitEntity.getVelocity(), org.bukkit.craftbukkit.util.CraftVector.toBukkit(velocity)
+                );
+                event.callEvent();
+
+                // Only change the target if actually needed, since we reset relative flags
+                if (!event.isCancelled() && event.getTo() != null && (!event.getTo().equals(event.getFrom()) || !event.getAfter().equals(event.getBefore()))) {
+                    to = event.getTo().clone();
+                    velocity = org.bukkit.craftbukkit.util.CraftVector.toNMS(event.getAfter());
+                    teleportTransition = new TeleportTransition(((org.bukkit.craftbukkit.CraftWorld) to.getWorld()).getHandle(), org.bukkit.craftbukkit.util.CraftLocation.toVec3D(to), velocity, to.getYaw(), to.getPitch(), teleportTransition.missingRespawnBlock(), teleportTransition.asPassenger(), Set.of(), teleportTransition.postTeleportTransition(), teleportTransition.cause());
+                }
+            }
+            if (this.isRemoved()) {
+                return null;
+            }
+            // Paper end - Call EntityPortalExitEvent
+            // CraftBukkit end
             ServerLevel level = teleportTransition.newLevel();
             boolean flag = level.dimension() != serverLevel.dimension();
             if (!teleportTransition.asPassenger()) {
@@ -2737,10 +_,19 @@
             profilerFiller.pop();
             return null;
         } else {
+            // Paper start - Fix item duplication and teleport issues
+            if (this instanceof Leashable leashable) {
+                leashable.dropLeash(); // Paper drop lead
+            }
+            // Paper end - Fix item duplication and teleport issues
             entityx.restoreFrom(this);
             this.removeAfterChangingDimensions();
+            // CraftBukkit start - Forward the CraftEntity to the new entity
+            //this.getBukkitEntity().setHandle(entity);
+            //entity.bukkitEntity = this.getBukkitEntity(); // Paper - forward CraftEntity in teleport command; moved to Entity#restoreFrom
+            // CraftBukkit end
             entityx.teleportSetPosition(PositionMoveRotation.of(teleportTransition), teleportTransition.relatives());
-            level.addDuringTeleport(entityx);
+            if (this.inWorld) level.addDuringTeleport(entityx); // CraftBukkit - Don't spawn the new entity if the current entity isn't spawned
 
             for (Entity entity2 : list) {
                 entity2.startRiding(entityx, true);
@@ -2814,9 +_,17 @@
     }
 
     protected void removeAfterChangingDimensions() {
-        this.setRemoved(Entity.RemovalReason.CHANGED_DIMENSION);
-        if (this instanceof Leashable leashable) {
-            leashable.removeLeash();
+        this.setRemoved(Entity.RemovalReason.CHANGED_DIMENSION, null); // CraftBukkit - add Bukkit remove cause
+        if (this instanceof Leashable leashable && leashable.isLeashed()) { // Paper - only call if it is leashed
+            // Paper start - Expand EntityUnleashEvent
+            final org.bukkit.event.entity.EntityUnleashEvent event = new org.bukkit.event.entity.EntityUnleashEvent(this.getBukkitEntity(), org.bukkit.event.entity.EntityUnleashEvent.UnleashReason.UNKNOWN, false); // CraftBukkit
+            event.callEvent();
+            if (!event.isDropLeash()) {
+                leashable.removeLeash();
+            } else {
+                leashable.dropLeash();
+            }
+            // Paper end - Expand EntityUnleashEvent
         }
     }
 
@@ -2824,11 +_,34 @@
         return PortalShape.getRelativePosition(portal, axis, this.position(), this.getDimensions(this.getPose()));
     }
 
+    // CraftBukkit start
+    public org.bukkit.craftbukkit.event.CraftPortalEvent callPortalEvent(Entity entity, org.bukkit.Location exit, org.bukkit.event.player.PlayerTeleportEvent.TeleportCause cause, int searchRadius, int creationRadius) {
+        org.bukkit.entity.Entity bukkitEntity = entity.getBukkitEntity();
+        org.bukkit.Location enter = bukkitEntity.getLocation();
+
+        // Paper start
+        final org.bukkit.PortalType portalType = switch (cause) {
+            case END_PORTAL -> org.bukkit.PortalType.ENDER;
+            case NETHER_PORTAL -> org.bukkit.PortalType.NETHER;
+            case END_GATEWAY -> org.bukkit.PortalType.END_GATEWAY; // not actually used yet
+            default -> org.bukkit.PortalType.CUSTOM;
+        };
+        org.bukkit.event.entity.EntityPortalEvent event = new org.bukkit.event.entity.EntityPortalEvent(bukkitEntity, enter, exit, searchRadius, true, creationRadius, portalType);
+        // Paper end
+        event.getEntity().getServer().getPluginManager().callEvent(event);
+        if (event.isCancelled() || event.getTo() == null || event.getTo().getWorld() == null || !entity.isAlive()) {
+            return null;
+        }
+        return new org.bukkit.craftbukkit.event.CraftPortalEvent(event);
+    }
+    // CraftBukkit end
+
     public boolean canUsePortal(boolean allowPassengers) {
         return (allowPassengers || !this.isPassenger()) && this.isAlive();
     }
 
     public boolean canTeleport(Level fromLevel, Level toLevel) {
+        if (!this.isAlive() || !this.valid) return false; // Paper - Fix item duplication and teleport issues
         if (fromLevel.dimension() == Level.END && toLevel.dimension() == Level.OVERWORLD) {
             for (Entity entity : this.getPassengers()) {
                 if (entity instanceof ServerPlayer serverPlayer && !serverPlayer.seenCredits) {
@@ -2936,9 +_,14 @@
         return this.entityData.get(DATA_CUSTOM_NAME_VISIBLE);
     }
 
-    public boolean teleportTo(ServerLevel level, double x, double y, double z, Set<Relative> relativeMovements, float yaw, float pitch, boolean setCamera) {
+    // CraftBukkit start
+    public final boolean teleportTo(ServerLevel level, double x, double y, double z, Set<Relative> relativeMovements, float yaw, float pitch, boolean setCamera) {
+        return this.teleportTo(level, x, y, z, relativeMovements, yaw, pitch, setCamera, org.bukkit.event.player.PlayerTeleportEvent.TeleportCause.UNKNOWN);
+    }
+    public boolean teleportTo(ServerLevel level, double x, double y, double z, Set<Relative> relativeMovements, float yaw, float pitch, boolean setCamera, org.bukkit.event.player.PlayerTeleportEvent.TeleportCause cause) {
+        // CraftBukkit end
         float f = Mth.clamp(pitch, -90.0F, 90.0F);
-        Entity entity = this.teleport(new TeleportTransition(level, new Vec3(x, y, z), Vec3.ZERO, yaw, f, relativeMovements, TeleportTransition.DO_NOTHING));
+        Entity entity = this.teleport(new TeleportTransition(level, new Vec3(x, y, z), Vec3.ZERO, yaw, f, relativeMovements, TeleportTransition.DO_NOTHING, cause)); // CraftBukkit
         return entity != null;
     }
 
@@ -3052,7 +_,26 @@
     }
 
     public final void setBoundingBox(AABB bb) {
-        this.bb = bb;
+        // CraftBukkit start - block invalid bounding boxes
+        double minX = bb.minX,
+                minY = bb.minY,
+                minZ = bb.minZ,
+                maxX = bb.maxX,
+                maxY = bb.maxY,
+                maxZ = bb.maxZ;
+        double len = bb.maxX - bb.minX;
+        if (len < 0) maxX = minX;
+        if (len > 64) maxX = minX + 64.0;
+
+        len = bb.maxY - bb.minY;
+        if (len < 0) maxY = minY;
+        if (len > 64) maxY = minY + 64.0;
+
+        len = bb.maxZ - bb.minZ;
+        if (len < 0) maxZ = minZ;
+        if (len > 64) maxZ = minZ + 64.0;
+        this.bb = new AABB(minX, minY, minZ, maxX, maxY, maxZ);
+        // CraftBukkit end
     }
 
     public final float getEyeHeight(Pose pose) {
@@ -3096,6 +_,12 @@
     }
 
     public void stopSeenByPlayer(ServerPlayer serverPlayer) {
+        // Paper start - entity tracking events
+        // Since this event cannot be cancelled, we should call it here to catch all "un-tracks"
+        if (io.papermc.paper.event.player.PlayerUntrackEntityEvent.getHandlerList().getRegisteredListeners().length > 0) {
+            new io.papermc.paper.event.player.PlayerUntrackEntityEvent(serverPlayer.getBukkitEntity(), this.getBukkitEntity()).callEvent();
+        }
+        // Paper end - entity tracking events
     }
 
     public float rotate(Rotation transformRotation) {
@@ -3129,7 +_,7 @@
     }
 
     @Nullable
-    public LivingEntity getControllingPassenger() {
+    public net.minecraft.world.entity.LivingEntity getControllingPassenger() {
         return null;
     }
 
@@ -3161,21 +_,32 @@
     }
 
     private Stream<Entity> getIndirectPassengersStream() {
+        if (this.passengers.isEmpty()) { return Stream.of(); } // Paper - Optimize indirect passenger iteration
         return this.passengers.stream().flatMap(Entity::getSelfAndPassengers);
     }
 
     @Override
     public Stream<Entity> getSelfAndPassengers() {
+        if (this.passengers.isEmpty()) { return Stream.of(this); } // Paper - Optimize indirect passenger iteration
         return Stream.concat(Stream.of(this), this.getIndirectPassengersStream());
     }
 
     @Override
     public Stream<Entity> getPassengersAndSelf() {
+        if (this.passengers.isEmpty()) { return Stream.of(this); } // Paper - Optimize indirect passenger iteration
         return Stream.concat(this.passengers.stream().flatMap(Entity::getPassengersAndSelf), Stream.of(this));
     }
 
     public Iterable<Entity> getIndirectPassengers() {
-        return () -> this.getIndirectPassengersStream().iterator();
+        // Paper start - Optimize indirect passenger iteration
+        if (this.passengers.isEmpty()) { return ImmutableList.of(); }
+        ImmutableList.Builder<Entity> indirectPassengers = ImmutableList.builder();
+        for (Entity passenger : this.passengers) {
+            indirectPassengers.add(passenger);
+            indirectPassengers.addAll(passenger.getIndirectPassengers());
+        }
+        return indirectPassengers.build();
+        // Paper end - Optimize indirect passenger iteration
     }
 
     public int countPlayerPassengers() {
@@ -3183,6 +_,7 @@
     }
 
     public boolean hasExactlyOnePlayerPassenger() {
+        if (this.passengers.isEmpty()) { return false; } // Paper - Optimize indirect passenger iteration
         return this.countPlayerPassengers() == 1;
     }
 
@@ -3260,9 +_,38 @@
         return 1;
     }
 
+    // CraftBukkit start
+    private final CommandSource commandSource = new CommandSource() {
+
+        @Override
+        public void sendSystemMessage(Component message) {
+        }
+
+        @Override
+        public org.bukkit.command.CommandSender getBukkitSender(CommandSourceStack wrapper) {
+            return Entity.this.getBukkitEntity();
+        }
+
+        @Override
+        public boolean acceptsSuccess() {
+            return ((ServerLevel) Entity.this.level()).getGameRules().getBoolean(net.minecraft.world.level.GameRules.RULE_SENDCOMMANDFEEDBACK);
+        }
+
+        @Override
+        public boolean acceptsFailure() {
+            return true;
+        }
+
+        @Override
+        public boolean shouldInformAdmins() {
+            return true;
+        }
+    };
+    // CraftBukkit end
+
     public CommandSourceStack createCommandSourceStackForNameResolution(ServerLevel level) {
         return new CommandSourceStack(
-            CommandSource.NULL, this.position(), this.getRotationVector(), level, 0, this.getName().getString(), this.getDisplayName(), level.getServer(), this
+            this.commandSource, this.position(), this.getRotationVector(), level, 0, this.getName().getString(), this.getDisplayName(), level.getServer(), this // CraftBukkit
         );
     }
 
@@ -3320,6 +_,11 @@
                                     vec3 = vec3.add(flow);
                                     i++;
                                 }
+                                // CraftBukkit start - store last lava contact location
+                                if (fluidTag == FluidTags.LAVA) {
+                                    this.lastLavaContact = mutableBlockPos.immutable();
+                                }
+                                // CraftBukkit end
                             }
                         }
                     }
@@ -3480,7 +_,39 @@
         return this.getZ((2.0 * this.random.nextDouble() - 1.0) * scale);
     }
 
+    // Paper start - Block invalid positions and bounding box
+    public static boolean checkPosition(Entity entity, double newX, double newY, double newZ) {
+        if (Double.isFinite(newX) && Double.isFinite(newY) && Double.isFinite(newZ)) {
+            return true;
+        }
+
+        String entityInfo;
+        try {
+            entityInfo = entity.toString();
+        } catch (Exception ex) {
+            entityInfo = "[Entity info unavailable] ";
+        }
+        LOGGER.error("New entity position is invalid! Tried to set invalid position ({},{},{}) for entity {} located at {}, entity info: {}", newX, newY, newZ, entity.getClass().getName(), entity.position, entityInfo, new Throwable());
+        return false;
+    }
     public final void setPosRaw(double x, double y, double z) {
+        this.setPosRaw(x, y, z, false);
+    }
+    public final void setPosRaw(double x, double y, double z, boolean forceBoundingBoxUpdate) {
+        if (!checkPosition(this, x, y, z)) {
+            return;
+        }
+        // Paper end - Block invalid positions and bounding box
+        // Paper start - Fix MC-4
+        if (this instanceof ItemEntity) {
+            if (io.papermc.paper.configuration.GlobalConfiguration.get().misc.fixEntityPositionDesync) {
+                // encode/decode from ClientboundMoveEntityPacket
+                x = Mth.lfloor(x * 4096.0) * (1 / 4096.0);
+                y = Mth.lfloor(y * 4096.0) * (1 / 4096.0);
+                z = Mth.lfloor(z * 4096.0) * (1 / 4096.0);
+            }
+        }
+        // Paper end - Fix MC-4
         if (this.position.x != x || this.position.y != y || this.position.z != z) {
             this.position = new Vec3(x, y, z);
             int floor = Mth.floor(x);
@@ -3496,6 +_,12 @@
 
             this.levelCallback.onMove();
         }
+        // Paper start - Block invalid positions and bounding box; don't allow desync of pos and AABB
+        // hanging has its own special logic
+        if (!(this instanceof net.minecraft.world.entity.decoration.HangingEntity) && (forceBoundingBoxUpdate || this.position.x != x || this.position.y != y || this.position.z != z)) {
+            this.setBoundingBox(this.makeBoundingBox());
+        }
+        // Paper end - Block invalid positions and bounding box
     }
 
     public void checkDespawn() {
@@ -3583,6 +_,15 @@
 
     @Override
     public final void setRemoved(Entity.RemovalReason removalReason) {
+        // CraftBukkit start - add Bukkit remove cause
+        this.setRemoved(removalReason, null);
+    }
+
+    @Override
+    public final void setRemoved(Entity.RemovalReason removalReason, org.bukkit.event.entity.EntityRemoveEvent.Cause cause) {
+        org.bukkit.craftbukkit.event.CraftEventFactory.callEntityRemoveEvent(this, cause);
+        // CraftBukkit end
+        final boolean alreadyRemoved = this.removalReason != null; // Paper - Folia schedulers
         if (this.removalReason == null) {
             this.removalReason = removalReason;
         }
@@ -3594,12 +_,28 @@
         this.getPassengers().forEach(Entity::stopRiding);
         this.levelCallback.onRemove(removalReason);
         this.onRemoval(removalReason);
+        // Paper start - Folia schedulers
+        if (!(this instanceof ServerPlayer) && removalReason != RemovalReason.CHANGED_DIMENSION && !alreadyRemoved) {
+            // Players need to be special cased, because they are regularly removed from the world
+            this.retireScheduler();
+        }
+        // Paper end - Folia schedulers
     }
 
     public void unsetRemoved() {
         this.removalReason = null;
     }
 
+    // Paper start - Folia schedulers
+    /**
+     * Invoked only when the entity is truly removed from the server, never to be added to any world.
+     */
+    public final void retireScheduler() {
+        // we need to force create the bukkit entity so that the scheduler can be retired...
+        this.getBukkitEntity().taskScheduler.retire();
+    }
+    // Paper end - Folia schedulers
+
     @Override
     public void setLevelCallback(EntityInLevelCallback levelCallback) {
         this.levelCallback = levelCallback;
@@ -3723,4 +_,14 @@
             return this.save;
         }
     }
+
+    // Paper start - Expose entity id counter
+    public static int nextEntityId() {
+        return ENTITY_COUNTER.incrementAndGet();
+    }
+
+    public boolean isTicking() {
+        return ((ServerLevel) this.level).isPositionEntityTicking(this.blockPosition());
+    }
+    // Paper end - Expose entity id counter
 }