@Override
public String getCreatorModId(ItemStack itemStack) {
	final Item item = itemStack.getItem();
	Identifier defaultId = Registry.ITEM.getDefaultId();
	Identifier id = Registry.ITEM.getId(item);

	if (defaultId.equals(id) && item != Registry.ITEM.get(defaultId)) {
		return null;
	} else {
		final String namespace = id.getNamespace();

		if ("minecraft".equals(namespace)) {
			final EntityType<?> type = ((SpawnEggItem) item).getEntityType(itemStack.getTag());
			id = Registry.ENTITY_TYPE.getId(type);
			defaultId = Registry.ENTITY_TYPE.getDefaultId();

			if (defaultId.equals(id) && type != Registry.ENTITY_TYPE.get(defaultId)) {
				return namespace;
			}

			return id.getNamespace();
		}

		return namespace;
	}
}
 

@Accessor("SPAWN_EGGS")
static Map<EntityType<?>, SpawnEggItem> getSpawnEggs() {
    return MixinHelper.fakeInstance();
}