The Crater Lake Monster is a 1977 horror film about a giant, prehistoric plesiosaur that kills people in a small Oregon town. Scientists Dan Turner (Richard Garrison) and Susan Patterson (Kacey Kobb) discover a cave that gives credence to the theory that dinosaurs and humans may have existed together. Not long after, a giant meteor crashes into the lake causing an incubating dinosaur egg to crack open. Panic grips the town after townspeople and tourists roaming in the vicinity of the lake get eaten. Sheriff Steve Hanson (Richard Cardella) is skeptical about the dinosaur sightings but investigates the killings after several cattle are found mutilated. After the body count continues to rise, the sheriff is convinced of the creature's existence and brings in Dan and Susan to help. In order to save the town, the sheriff, Dan and Susan must devise a plan get rid of the menacing creature once and for all.