While poking around YouTube I found a neat video of Leucochloridium paradoxum in action. L. paradoxum is a parasitic flatworm that rotates between two hosts: a snail and a bird. Adult worms live inside a bird’s rectum, eating the predigested wastes that pass by them and releasing eggs that leave the bird in its feces. The eggs don’t hatch immediately. Instead, they wait for a snail of the genus Succinea to find them and eat them. Then things get interesting.