9. Gunnery Sgt. Hartman (Full Metal Jacket)
Here's another one that's pretty obvious, to the point that the source material is even mentioned in the film itself. Though the brash douchebag drill instructor has become something of a cliche, its most famous association stems from Stanley Kubrick's superb film Full Metal Jacket, in which R. Lee Ermey plays Gunnery Sgt. Hartman, a cantankerous officer who takes to whipping his boys into shape in the most hilariously profane manner possible. Hartman refers to the clumsiest officer in the unit, Pvt. Lawrence (Vincent D'Onofrio), as "Gomer Pyle", a direct reference to the show Gomer Pyle U.S.M.C. about the titular character who enlists in the Marine Corps, and is subject to abuse from a ruthless drill instructor called Gunnery Sgt. Vince Carter. Though, unlike Kubrick's film, the character eventually turns nice (due to the audience apparently wanting something more family friendly), the parallels are obvious. It's pretty clever of Kubrick, really; he directly references the source material in a way that will fly over most people's heads. Therefore it's hard for people to say he's secretly stealing from other works, and most people will never even be aware that he is.