AquaDoug
An AquaDoug is a creature originating as homo sapien but slowly evolving into a new species upon being bitten by a large, toothy, lake-dwelling fish - such as a muskellunge. The noticeable characteristics of an AquaDoug include; development of gills, sharp front teeth, an affinity for eating other fish, and impeccable swimming skills.
Did you see that giant fish turn that guy into an AquaDoug?!?