There is a grade B horror movie lurking in this event. Perhaps “The Attack of The Killer Beavers.” A Group of teens are happily camping near a beaver dam. The really cute blond wanders off at night her last scene depicts a giant shadow creeping up on her.....
Terror in the swamp.
http://www.imdb.com/title/tt0090149/
In an effort to create the perfect nutria for breeding by the fur industry, a scientist and his assistant inadvertently create a brutal mutation that escapes into the nearby swamps.