The Manster (1959)

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-headed monster.

The Manster is a horror movie featuring Peter Dyneley and directed by George P. Breakston.

The Manster is currently streaming for free (ad-supported) on Darkmatter TV, DistroTV, Plex, Plex Player and Tubi TV and it's also available on Amazon Prime Video, Classix, MGM Plus Roku Premium Channel, Paramount Plus Apple TV Channel and fuboTV.

It is also possible to buy The Manster on Amazon Video.