KAMOSS

Take care if you venture near the Klamath River in California.  Native American tradition holds that in it lurks the Kamoss, a huge snake.  The beast was known to the Native Americans and can find its way into sewers.  My source, David Paulides' book The Hoopa Project, is unclear whether there is supposed to be just one of these or a population.  Whichever, swim carefully in this body of water or, safer still, not at all.