大象传媒

A parasite (fluke) lives within the eye tentacle of a snail, making it pulsate eerily. It needs a bird to eat the snail, so that it can spread its offspring to other hosts. The fluke causes the snail to alter its behaviour so does not hide away and is more likely to get eaten by a bird. A bird eats the snail and the parasite's eggs hatch out within it.