Hellmaster (also known as Soulstealer and Them) is a 1992 American horror film written and directed by Douglas Schulze, and starring John Saxon. The plot follows a psychotic college professor who uses unsuspecting students as laboratory rats, injecting them with a drug that mutates them into brutal killers.

The film has been observed to be largely influenced by the Nightmare on Elm Street series – which also featured Saxon – as well as other popular horror titles such as Hellraiser.