That's one heck of a commit you've got there...

I may have got a bit behind with version control. A lot behind, in fact. Maybe I'll go back and split this sometime - then again, I probably won't. But hey, at least it's here!

src/main/java/electroblob/wizardry/entity/living/EntitySummonedCreature.java

@@ -1,8 +1,5 @@
 package electroblob.wizardry.entity.living;
 
-import java.lang.ref.WeakReference;
-import java.util.UUID;
-
 import electroblob.wizardry.Wizardry;
 import net.minecraft.entity.EntityCreature;
 import net.minecraft.entity.EntityFlying;
@@ -14,8 +11,11 @@ import net.minecraft.util.EnumHand;
 import net.minecraft.util.ResourceLocation;
 import net.minecraft.util.text.ITextComponent;
 import net.minecraft.util.text.TextComponentTranslation;
+import net.minecraft.world.EnumDifficulty;
 import net.minecraft.world.World;
 
+import java.util.UUID;
+
 /**
  * Abstract base implementation of {@link ISummonedCreature} which is the superclass to all custom summoned entities
  * (i.e. entities that don't extend vanilla/mod creatures). Also serves as an example of how to correctly implement the
@@ -29,8 +29,7 @@ import net.minecraft.world.World;
 public abstract class EntitySummonedCreature extends EntityCreature implements ISummonedCreature {
 
 	// Field implementations
-	private int lifetime = 600;
-	private WeakReference<EntityLivingBase> casterReference;
+	private int lifetime = -1;
 	private UUID casterUUID;
 
 	// Setter + getter implementations
@@ -45,22 +44,12 @@ public abstract class EntitySummonedCreature extends EntityCreature implements I
 	}
 
 	@Override
-	public WeakReference<EntityLivingBase> getCasterReference(){
-		return casterReference;
-	}
-
-	@Override
-	public void setCasterReference(WeakReference<EntityLivingBase> reference){
-		casterReference = reference;
-	}
-
-	@Override
-	public UUID getCasterUUID(){
+	public UUID getOwnerId(){
 		return casterUUID;
 	}
 
 	@Override
-	public void setCasterUUID(UUID uuid){
+	public void setOwnerId(UUID uuid){
 		this.casterUUID = uuid;
 	}
 
@@ -122,8 +111,16 @@ public abstract class EntitySummonedCreature extends EntityCreature implements I
 	@Override protected Item getDropItem(){ return null; }
 	@Override protected ResourceLocation getLootTable(){ return null; }
 	@Override public boolean canPickUpLoot(){ return false; }
+
 	// This vanilla method has nothing to do with the custom despawn() method.
-	@Override protected boolean canDespawn(){ return false; }
+	@Override protected boolean canDespawn(){
+		return getCaster() == null && getOwnerId() == null;
+	}
+
+	@Override
+	public boolean getCanSpawnHere(){
+		return this.world.getDifficulty() != EnumDifficulty.PEACEFUL;
+	}
 
 	@Override
 	public boolean canAttackClass(Class<? extends EntityLivingBase> entityType){
@@ -144,7 +141,7 @@ public abstract class EntitySummonedCreature extends EntityCreature implements I
 	@Override
 	public boolean hasCustomName(){
 		// If this returns true, the renderer will show the nameplate when looking directly at the entity
-		return Wizardry.settings.showSummonedCreatureNames && getCaster() != null;
+		return Wizardry.settings.summonedCreatureNames && getCaster() != null;
 	}
 
 	// Specific to EntitySummonedCreature, remove if copying