Fiend Without A Face is based on a 1930s pulp magazine story called "The Thought Monster". Marshall Thompson is a Major on an air force base in Canada. The military is developing long range radar that uses nuclear power. The local farmers are upset because the jets are noisy and frightening the cows causing them to under-produce milk. But much worse, some of the locals are found dead with their brains sucked out of two small holes in the back of their necks. Eeek!
Thompson investigates Professor Walgate who seems to have something to do with it all.
Fiend is a standard grade-B sci-fi flick from the 50s. I happen to be a sucker for 1950s grade B movies. I actually love them even though they are not very good usually. If you are like me you'll like Fiend. The acting and dialog varies from average to embarrassing and most of the film is pretty boring, but it's short.
The monsters are invisible until the end but they are interesting movie creations. They're done with stop-animation. They should be comical but for some strange reason I've always found them extremely creepy.
If you've seen It The Terror From Beyond Space with Thompson you have an idea of the quality of Fiend.