Val Guest (The Day the Earth Caught Fire) directed this chilling film about a spacecraft returning to earth with a frightening surprise on board. Two of the ship's three astronauts have mysteriously vanished, while the third is sick with an unidentifiable illness. While doctors try to help the third man recover, an investigation takes place to figure out just what happened to his comrades. As it turns out, the survivors body has been taken over by an alien fungus that needs blood to survive. After the astronaut escapes from the hospital, he transforms into a monster, attacking everyone who gets in its way. Meanwhile, Scotland Yard detective Lomax (Jack Warner, The Blue Lamp) and Professor Bernard Quatermass (Brian Donlevy, The Glass Key), a determined scientist, attempt to track down the creature before it finds new victims. Also known as The Creeping Unknown.