In some levels like creeper forest there are some enemis that either spawn or clip through a wall and become useless since they can't attack me and I can't attack them, something similar happens with the llama, the wolf and the iron golem, sometimes when I use the item to either spawn it or call it, the pet would randomly start falling through the floor infinitely until I move to a higher or lower terrain, I don't really know what causes it but it's rather annoyng.