Mr. Sir (real name: Marion Sevillo) is the secondary main antagonist from the book Holes and the 2003 Disney adventure/comedy-drama movie adaption of the same name.
He was portrayed by Jon Voight who also played Bill Biscane in Baby Geniuses 2.
He is an officer at the boys prison camp, Camp Green Lake. He always has an angry attitude due to his withdrawal of alcohol and tobacco, and may be totally mentally unstable. He doesn't get along with anybody, not even Mr. Pendanski, the camp members, or the Warden. He carries a pistol, which he uses to defend himself (and on one known occasion, Stanley Yelnats, the story's main protagonist) against the deadly yellow-spotted lizards. His fate differs in the book and movie: in the book, he simply gives Stanley his backpack after the latter is cleared of all charges, while in the movie, he is revealed to be a criminal who violated his parole by carrying a pistol (the policeman who originally arrested him happened to conveniently be at the camp and recognized him) and is arrested. In the latter ending, the officer reveals that Mr. Sir's real name is Marion Sevillo, much to the amusement of the campers.
He has a habit of saying "this ain't a girl scout camp." Ironically, Camp Green Lake becomes a girl scout camp after the Warden loses ownership of the property. He also took to eating sunflower seeds to compensate for his lack of cigarettes, though he started smoking again near the end of the movie because sunflower seeds "didn't work for him."