The Manster (1959)

Stars: Peter Dyneley, Jane Hylton and Tetsu Nakamura
Directors: George P. Breakston, Kenneth G. Crane

An American reporter in Japan is sent to interview an eccentric Japanese scientist working on bizarre experiments in his mountain laboratory. When the doctor realizes that the hapless correspondent is the perfect subject for his next experiment, he drugs the unfortunate man and injects him with a serum that gradually transforms him into a hideous, two-head manster!