YTS.MX: YIFY Movies (the only official YIFY site) at https://yts.mx
The Legend of Boggy Creek (1972) [720p] [WEBRip] [YTS] [YIFY] A documentary-style drama which questions the existence of a monster in an Arkansas swamp. It is really more of a glimpse at lower-class swamp culture from the seventies, though, than a monster flick.
A documentary-style drama based on true accounts of the Fouke Monster in Arkansas, Boggy Creek focuses on the lives of back country people and their culture while chronicling sightings of the monster.