3-Demon (also known as Monster Maze, though not to be confused with 3D Monster Maze) is a wireframe 1983 DOS computer game based on Pac-Man. Coincidentally, Wolfenstein 3D, a title widely thought to have later popularized the first-person shooter genre, featured a secret level based on Pac-Man and early in its development designer Tom Hall had suggested a name along the lines of "3-Demon" before id Software decided to do a semi-remake of the once popular Apple II game Castle Wolfenstein.