One of the most chilling bad guys I've ever seen on film is in a soft-core sex flick -- a Russ Meyer movie, even. If you think of Meyer only as the director who featured supremely large-chested women in his films, you probably haven't seen his 1975 film Supervixens. Sure, there are plenty of voluptuous females in the movie, and some comedy moments, but there's also Charles Napier, and his character is truly villainous.
Supervixens is about an ordinary guy, Clint, who's married to the title character, a bad-tempered tease who is brutally murdered by an even nastier cop, Harry Sledge (Napier). Clint -- who is honestly the least memorable part of the movie -- flees town to avoid Sledge, and ends up encountering all kinds of delightful women whose names begin with "Super," like Supersoul, SuperCherry, and SuperHaji. His soulmate, though, is the amazing SuperAngel, played by the same actress as SuperVixen, Shari Eubank. Just as Clint is ready to settle down to a happy ending with SuperAngel, Harry Sledge returns.
Charles Napier's characters are nearly always scary on some level -- you're most likely to have seen him as the head Good Old Boy in The Blues Brothers. Remember that big, psychotic smile? I've never seen him play anyone I didn't want to hide from ... except in Married to the Mob, where he's cast entirely against type as a hairdresser. In Supervixens, his Harry Sledge is merciless and ruthless and downright insane. I've always wondered if Willem Dafoe's character in Wild at Heart, Bobby Peru, wasn't somehow based on Sledge -- there are definitely similarities in what they do and when. But Harry Sledge, with an apple-pie American appearance masking his psychotic sadism, strikes me as the more fearsome of the two.
YouTube has a clip from Supervixens, in which Sledge is taunted by SuperVixen until he becomes horrifyingly violent, but it is restricted so minors can't view it -- you have to have an account or otherwise prove you're at least 18. Because it is a seriously graphic scene, probably the most disturbing scene in the film, I'm not embedding the video. Follow the above link to watch it, and bear in mind that it's definitely not safe for viewing in your office or other public place.