A normal snapping turtle
Big Blue is an Iowa cryptid, said to dwell in a Mason City pond of the same name. While its appearance is that of a normal snapping turtle, it is the size of the hood of a Volkswagen. Turtles of this size do exist, but not in Iowa. Because the Big Blue pond is a hot spot for scuba divers, most sightings are made by them. People who doubt the creature's existence claim that turtles of that size prefer marshes, creeks, or small rivers; not ponds.