--- a/net/minecraft/world/entity/AreaEffectCloud.java
+++ b/net/minecraft/world/entity/AreaEffectCloud.java
@@ -33,6 +33,12 @@
 import net.minecraft.world.level.material.PushReaction;
 import org.slf4j.Logger;
 
+// CraftBukkit start
+import org.bukkit.craftbukkit.entity.CraftLivingEntity;
+import org.bukkit.entity.LivingEntity;
+import org.bukkit.event.entity.EntityRemoveEvent;
+// CraftBukkit end
+
 public class AreaEffectCloud extends Entity implements TraceableEntity {
 
     private static final Logger LOGGER = LogUtils.getLogger();
@@ -54,7 +60,7 @@
     public float radiusOnUse;
     public float radiusPerTick;
     @Nullable
-    private LivingEntity owner;
+    private net.minecraft.world.entity.LivingEntity owner;
     @Nullable
     public UUID ownerUUID;
 
@@ -145,7 +151,19 @@
         this.duration = duration;
     }
 
+    // Spigot start - copied from below
     @Override
+    public void inactiveTick() {
+        super.inactiveTick();
+
+        if (this.tickCount >= this.waitTime + this.duration) {
+            this.discard(EntityRemoveEvent.Cause.DESPAWN); // CraftBukkit - add Bukkit remove cause
+            return;
+        }
+    }
+    // Spigot end
+
+    @Override
     public void tick() {
         super.tick();
         Level world = this.level();
@@ -200,7 +218,7 @@
 
     private void serverTick(ServerLevel world) {
         if (this.tickCount >= this.waitTime + this.duration) {
-            this.discard();
+            this.discard(EntityRemoveEvent.Cause.DESPAWN); // CraftBukkit - add Bukkit remove cause
         } else {
             boolean flag = this.isWaiting();
             boolean flag1 = this.tickCount < this.waitTime;
@@ -215,7 +233,7 @@
                 if (this.radiusPerTick != 0.0F) {
                     f += this.radiusPerTick;
                     if (f < 0.5F) {
-                        this.discard();
+                        this.discard(EntityRemoveEvent.Cause.DESPAWN); // CraftBukkit - add Bukkit remove cause
                         return;
                     }
 
@@ -244,16 +262,17 @@
                         }
 
                         list.addAll(this.potionContents.customEffects());
-                        List<LivingEntity> list1 = this.level().getEntitiesOfClass(LivingEntity.class, this.getBoundingBox());
+                        List<net.minecraft.world.entity.LivingEntity> list1 = this.level().getEntitiesOfClass(net.minecraft.world.entity.LivingEntity.class, this.getBoundingBox());
 
                         if (!list1.isEmpty()) {
                             Iterator iterator1 = list1.iterator();
 
+                            List<LivingEntity> entities = new java.util.ArrayList<LivingEntity>(); // CraftBukkit
                             while (iterator1.hasNext()) {
-                                LivingEntity entityliving = (LivingEntity) iterator1.next();
+                                net.minecraft.world.entity.LivingEntity entityliving = (net.minecraft.world.entity.LivingEntity) iterator1.next();
 
                                 if (!this.victims.containsKey(entityliving) && entityliving.isAffectedByPotions()) {
-                                    Stream stream = list.stream();
+                                    Stream<MobEffectInstance> stream = list.stream(); // CraftBukkit - decompile error
 
                                     Objects.requireNonNull(entityliving);
                                     if (!stream.noneMatch(entityliving::canBeAffected)) {
@@ -262,6 +281,19 @@
                                         double d2 = d0 * d0 + d1 * d1;
 
                                         if (d2 <= (double) (f * f)) {
+                                            // CraftBukkit start
+                                            entities.add((LivingEntity) entityliving.getBukkitEntity());
+                                        }
+                                    }
+                                }
+                            }
+                            {
+                                org.bukkit.event.entity.AreaEffectCloudApplyEvent event = org.bukkit.craftbukkit.event.CraftEventFactory.callAreaEffectCloudApplyEvent(this, entities);
+                                if (!event.isCancelled()) {
+                                    for (LivingEntity entity : event.getAffectedEntities()) {
+                                        if (entity instanceof CraftLivingEntity) {
+                                            net.minecraft.world.entity.LivingEntity entityliving = ((CraftLivingEntity) entity).getHandle();
+                                            // CraftBukkit end
                                             this.victims.put(entityliving, this.tickCount + this.reapplicationDelay);
                                             Iterator iterator2 = list.iterator();
 
@@ -271,14 +303,14 @@
                                                 if (((MobEffect) mobeffect1.getEffect().value()).isInstantenous()) {
                                                     ((MobEffect) mobeffect1.getEffect().value()).applyInstantenousEffect(world, this, this.getOwner(), entityliving, mobeffect1.getAmplifier(), 0.5D);
                                                 } else {
-                                                    entityliving.addEffect(new MobEffectInstance(mobeffect1), this);
+                                                    entityliving.addEffect(new MobEffectInstance(mobeffect1), this, org.bukkit.event.entity.EntityPotionEffectEvent.Cause.AREA_EFFECT_CLOUD); // CraftBukkit
                                                 }
                                             }
 
                                             if (this.radiusOnUse != 0.0F) {
                                                 f += this.radiusOnUse;
                                                 if (f < 0.5F) {
-                                                    this.discard();
+                                                    this.discard(EntityRemoveEvent.Cause.DESPAWN); // CraftBukkit - add Bukkit remove cause
                                                     return;
                                                 }
 
@@ -288,7 +320,7 @@
                                             if (this.durationOnUse != 0) {
                                                 this.duration += this.durationOnUse;
                                                 if (this.duration <= 0) {
-                                                    this.discard();
+                                                    this.discard(EntityRemoveEvent.Cause.DESPAWN); // CraftBukkit - add Bukkit remove cause
                                                     return;
                                                 }
                                             }
@@ -336,14 +368,14 @@
         this.waitTime = waitTime;
     }
 
-    public void setOwner(@Nullable LivingEntity owner) {
+    public void setOwner(@Nullable net.minecraft.world.entity.LivingEntity owner) {
         this.owner = owner;
         this.ownerUUID = owner == null ? null : owner.getUUID();
     }
 
     @Nullable
     @Override
-    public LivingEntity getOwner() {
+    public net.minecraft.world.entity.LivingEntity getOwner() {
         if (this.owner != null && !this.owner.isRemoved()) {
             return this.owner;
         } else {
@@ -353,10 +385,10 @@
                 if (world instanceof ServerLevel) {
                     ServerLevel worldserver = (ServerLevel) world;
                     Entity entity = worldserver.getEntity(this.ownerUUID);
-                    LivingEntity entityliving;
+                    net.minecraft.world.entity.LivingEntity entityliving;
 
-                    if (entity instanceof LivingEntity) {
-                        LivingEntity entityliving1 = (LivingEntity) entity;
+                    if (entity instanceof net.minecraft.world.entity.LivingEntity) {
+                        net.minecraft.world.entity.LivingEntity entityliving1 = (net.minecraft.world.entity.LivingEntity) entity;
 
                         entityliving = entityliving1;
                     } else {