SPIGOT-4128: Skip hopeless entity conversion

src/main/java/org/bukkit/craftbukkit/inventory/CraftMetaSpawnEgg.java

@@ -81,7 +81,8 @@ public class CraftMetaSpawnEgg extends CraftMetaItem implements SpawnEggMeta {
 
             // Tag still has some other data, lets try our luck with a conversion
             if (!entityTag.isEmpty()) {
-                entityTag = (NBTTagCompound) MinecraftServer.getServer().dataConverterManager.update(DataConverterTypes.ENTITY, new Dynamic(DynamicOpsNBT.a, entityTag), -1, CraftMagicNumbers.DATA_VERSION).getValue();
+                // SPIGOT-4128: This is hopeless until we start versioning stacks. RIP data.
+                // entityTag = (NBTTagCompound) MinecraftServer.getServer().dataConverterManager.update(DataConverterTypes.ENTITY, new Dynamic(DynamicOpsNBT.a, entityTag), -1, CraftMagicNumbers.DATA_VERSION).getValue();
             }
 
             // See if we can read a converted ID tag