This is from the 1976 classic Water Power. It's a lot like Taxi Driver, except this Travis Bickle has a little fetish for forcing woman into doing enemas at gun point. The film is actually based on real crimes committed by an Illinois man dubbed the "Enema Bandit". Anyway he's dead now, so R.I.P you scat-loving motherfucker.
Just close your eyes and listen to the audio. Only time I've heard a man make sounds like that was in Al-Qaeda beheading video. See more from this awesome couple here: 1, 2 and 3.