Leucochloridium paradoxum

Ah, the parasitic flatworms called trematodes. There's a lot of them, and many have very strange and impressive life cycles involving many specific hosts. Just about any of them is sci-fi worthy, but this one, in particular, is a real eye-catcher. Meet Leucochloridium paradoxum, also known as the green-banded broodsac. Like similar flatworms, its lifecycle involves two hosts. The adults, found in the guts of birds, lay eggs which land on the ground in the bird's droppings. The unfortunate host to follow, a snail (Succinea or Oxyloma), then eats the eggs, which hatch in its digestive system…