The Manster is a great little film that far more people should know about. It is one of those old horror/sci-fi B-movie type things but whereas most of them are awful, cheap, quickly made affairs this one seems a little more considered.
Filmed in 1959 you can forgive the sometimes ropey effects as the story and characterisation is generally good. The scientist character is both pioneering and menacing at the same time and the main character is suitably three dimensional.
The women never get hysterical and there is a strange morality behind it all.
Hard to find, but worth finding.