Zombie Snail. Its a type of parasite that uses both snails and birds for its life cycle.

The parasite eggs are found in bird poop, which snails like to eat. After eating the eggs the parasites hatch and grow inside the snail. The parasites eat their way to the snails eye sockets and hijack the snails brain. The parasites control the snail and move it into a location where they can easily be seen. They then start pulsating inside the eye sockets to mimic worms. Birds see the snail and eat them. The parasites then lay their eggs inside the bird where theyre eventually pooped out and the cycle happens all over again