The Manster (双頭の殺人鬼, Sōtō no Satsujinki, "The Two-Headed Killer") is an American science-fiction horror film. Shot in Japan, it was produced by George P. Breakston and directed by Breakston and Kenneth G. Crane from a screenplay by Walter J. Sheldon. Sheldon's script was based on Breakston's story which he originally titled The Split.