--- a/net/minecraft/world/entity/monster/EntityZombie.java
+++ b/net/minecraft/world/entity/monster/EntityZombie.java
@@ -70,6 +70,15 @@
 import net.minecraft.world.level.block.Blocks;
 import net.minecraft.world.level.block.state.IBlockData;
 
+// CraftBukkit start
+import net.minecraft.server.MinecraftServer;
+import org.bukkit.entity.Zombie;
+import org.bukkit.event.entity.CreatureSpawnEvent;
+import org.bukkit.event.entity.EntityCombustByEntityEvent;
+import org.bukkit.event.entity.EntityTargetEvent;
+import org.bukkit.event.entity.EntityTransformEvent;
+// CraftBukkit end
+
 public class EntityZombie extends EntityMonster {
 
     private static final UUID SPEED_MODIFIER_BABY_UUID = UUID.fromString("B9766B59-9566-4402-BC1F-2EE2A276D836");
@@ -89,6 +98,7 @@
     private boolean canBreakDoors;
     private int inWaterTime;
     public int conversionTime;
+    private int lastTick = MinecraftServer.currentTick; // CraftBukkit - add field
 
     public EntityZombie(EntityTypes<? extends EntityZombie> entitytypes, World world) {
         super(entitytypes, world);
@@ -205,7 +215,10 @@
     public void tick() {
         if (!this.level.isClientSide && this.isAlive() && !this.isNoAI()) {
             if (this.isDrownConverting()) {
-                --this.conversionTime;
+                // CraftBukkit start - Use wall time instead of ticks for conversion
+                int elapsedTicks = MinecraftServer.currentTick - this.lastTick;
+                this.conversionTime -= elapsedTicks;
+                // CraftBukkit end
                 if (this.conversionTime < 0) {
                     this.fy();
                 }
@@ -222,6 +235,7 @@
         }
 
         super.tick();
+        this.lastTick = MinecraftServer.currentTick; // CraftBukkit
     }
 
     @Override
@@ -254,6 +268,7 @@
     }
 
     public void startDrownedConversion(int i) {
+        this.lastTick = MinecraftServer.currentTick; // CraftBukkit
         this.conversionTime = i;
         this.getDataWatcher().set(EntityZombie.DATA_DROWNED_CONVERSION_ID, true);
     }
@@ -267,11 +282,15 @@
     }
 
     protected void b(EntityTypes<? extends EntityZombie> entitytypes) {
-        EntityZombie entityzombie = (EntityZombie) this.a(entitytypes, true);
+        EntityZombie entityzombie = (EntityZombie) this.a(entitytypes, true, EntityTransformEvent.TransformReason.DROWNED, CreatureSpawnEvent.SpawnReason.DROWNED);
 
         if (entityzombie != null) {
             entityzombie.z(entityzombie.level.getDamageScaler(entityzombie.getChunkCoordinates()).d());
             entityzombie.w(entityzombie.p() && this.fD());
+            // CraftBukkit start - SPIGOT-5208: End conversion to stop event spam
+        } else {
+            ((Zombie) getBukkitEntity()).setConversionTime(-1);
+            // CraftBukkit end
         }
 
     }
@@ -311,9 +330,9 @@
                     if (SpawnerCreature.a(entitypositiontypes_surface, (IWorldReader) this.level, blockposition, entitytypes) && EntityPositionTypes.a(entitytypes, worldserver, EnumMobSpawn.REINFORCEMENT, blockposition, this.level.random)) {
                         entityzombie.setPosition((double) i1, (double) j1, (double) k1);
                         if (!this.level.isPlayerNearby((double) i1, (double) j1, (double) k1, 7.0D) && this.level.f((Entity) entityzombie) && this.level.getCubes(entityzombie) && !this.level.containsLiquid(entityzombie.getBoundingBox())) {
-                            entityzombie.setGoalTarget(entityliving);
+                            entityzombie.setGoalTarget(entityliving, EntityTargetEvent.TargetReason.REINFORCEMENT_TARGET, true); // CraftBukkit
                             entityzombie.prepare(worldserver, this.level.getDamageScaler(entityzombie.getChunkCoordinates()), EnumMobSpawn.REINFORCEMENT, (GroupDataEntity) null, (NBTTagCompound) null);
-                            worldserver.addAllEntities(entityzombie);
+                            worldserver.addAllEntities(entityzombie, CreatureSpawnEvent.SpawnReason.REINFORCEMENTS); // CraftBukkit
                             this.getAttributeInstance(GenericAttributes.SPAWN_REINFORCEMENTS_CHANCE).addModifier(new AttributeModifier("Zombie reinforcement caller charge", -0.05000000074505806D, AttributeModifier.Operation.ADDITION));
                             entityzombie.getAttributeInstance(GenericAttributes.SPAWN_REINFORCEMENTS_CHANCE).addModifier(new AttributeModifier("Zombie reinforcement callee charge", -0.05000000074505806D, AttributeModifier.Operation.ADDITION));
                             break;
@@ -334,7 +353,14 @@
             float f = this.level.getDamageScaler(this.getChunkCoordinates()).b();
 
             if (this.getItemInMainHand().isEmpty() && this.isBurning() && this.random.nextFloat() < f * 0.3F) {
-                entity.setOnFire(2 * (int) f);
+                // CraftBukkit start
+                EntityCombustByEntityEvent event = new EntityCombustByEntityEvent(this.getBukkitEntity(), entity.getBukkitEntity(), 2 * (int) f); // PAIL: fixme
+                this.level.getCraftServer().getPluginManager().callEvent(event);
+
+                if (!event.isCancelled()) {
+                    entity.setOnFire(event.getDuration(), false);
+                }
+                // CraftBukkit end
             }
         }
 
@@ -415,7 +441,12 @@
             }
 
             EntityVillager entityvillager = (EntityVillager) entityliving;
-            EntityZombieVillager entityzombievillager = (EntityZombieVillager) entityvillager.a(EntityTypes.ZOMBIE_VILLAGER, false);
+            // CraftBukkit start
+            EntityZombieVillager entityzombievillager = (EntityZombieVillager) entityvillager.a(EntityTypes.ZOMBIE_VILLAGER, false, EntityTransformEvent.TransformReason.INFECTION, CreatureSpawnEvent.SpawnReason.INFECTION);
+            if (entityzombievillager == null) {
+                return;
+            }
+            // CraftBukkit end
 
             entityzombievillager.prepare(worldserver, worldserver.getDamageScaler(entityzombievillager.getChunkCoordinates()), EnumMobSpawn.CONVERSION, new EntityZombie.GroupDataZombie(false, true), (NBTTagCompound) null);
             entityzombievillager.setVillagerData(entityvillager.getVillagerData());
@@ -472,7 +503,7 @@
                         entitychicken1.prepare(worldaccess, difficultydamagescaler, EnumMobSpawn.JOCKEY, (GroupDataEntity) null, (NBTTagCompound) null);
                         entitychicken1.setChickenJockey(true);
                         this.startRiding(entitychicken1);
-                        worldaccess.addEntity(entitychicken1);
+                        worldaccess.addEntity(entitychicken1, CreatureSpawnEvent.SpawnReason.MOUNT); // CraftBukkit
                     }
                 }
             }