The Manster (1959, aka The Split aka Doktor Satan) builds up an unexpectedly impressive number of positive assets, including the unusual title, before wasting them in a vague climax. Peter Dyneley plays Larry Stanford, a foreign correspondent based in Japan who is faced with his final assignment before returning home to his wife: an interview with a reclusive scientist with unknown research interests. He visits the scientist, a Doctor Suzuki, as his lab on a volcano, and Suzuki drugs Larry and uses him in his latest research experiment: an attempt to split man into his basic good side and bad side (a possible inspiration for a later Star Trek episode?). Larry knows nothing, and is released by the smiling doctor Suzuki as if nothing had happened.
Larry rapidly becomes a grumpy curmudgeon, no longer the cheerful professional looking forward to spending time with his wife, but rather carousing with the scientist’s amoral assistant. Then events take a turn for the worse, bodies begin to pile up, and reluctant suspicion is focused on the foreigner who has frequent temper tantrums. As his transformation begins …
… we acknowledge and admire the general level of acting quality. In particular, one of the failed experiments manages to “chew the scenery” with particularly good effect. The regular people are well-played, and if the wife doesn’t stand out as much as she might, she could have used some better lines as well. And the scientist, whose motivations are never elaborated, is a mysterious character right to the end, pursuing obtuse goals and experiencing regrets of strange character that leaves us wondering if he’s really as different as he seems – or if the scriptwriter imbibed even more than Larry, who seems to live on booze.
The special effects range from the absolutely worst volcanic explosion committed to film to quite creditable makeup jobs on the victims of the experiments. It was actually not hard to buy into the results depicted.
But the story … oh the story … woe is the story. Although it gets off to a good start, showing us enough to hook us without overdoing it, it loses its way as Larry devolves more and more. Logic is lost as it should have shown Larry ingesting all the food he could possibly eat, given what’s happening to him, but instead he indulges in aimless murders. In much the same way, the story runs off into a series of aimless events, along with minor titillation, and finally a dreary chase of the monster Larry which drags on and on. And, predictably (the dread foe of good stories), all the bad and even ambiguous characters meet their fate, while Larry miraculously survives, scrubbed of his sins and united with his wife. A promising beginning is wasted on an inorganic and pat ending, a pity given some of those assets they had constructed.
