Flatworm

Flatworms are creatures mentioned

Background
West-Tek experimented with different species of flatworms, infecting them with the Forced Evolutionary Virus. Within hours, the worms increased in size by 28% and all subjects resisted 39 separate viral contagions. They were allowed continue for several generations exclusively through asexual reproduction. New DNA structures introduced by FEV were successfully passed onto the offspring.

Appearances
Flatworms are mentioned