In the southern states of America a strange story of mutant frogs emerged, appearing with extra limbs and other deformities. These mysterious mutants were believed to be the result of chemical or radioactive pollution, but the full story is stranger still. Herons that eat these mutant frogs also acquire their parasites, these birds pass the eggs of the parasitic flat worms in their droppings into the water. Snails in the water eat the eggs which soon hatch and emerge as mini parasites. Each of these parasites then searches for the nearest tadpole. With torpedo precision it tracks it target, aiming for the limb buds. As the parasite burrows inside, the cells explode, the fragmented limb buds try to regrow but in the process they create several legs instead of one. The parasite creates a mutant for one simple purpose, deformed frogs make easy prey. For the gruesome life cycle to continue the host must be eaten by a heron.