The Quatermass Xperiment

The Quatermass Xperiment (U.S. title: The Creeping Unknown) is a 1955 film about three astronauts who are launched into space aboard a rocket designed by Professor Quatermass, but the spacecraft returns to earth with only one occupant, Victor Carroon. Something has infected him during the spaceflight, and he begins mutating into an alien organism which, if it spores, will engulf the Earth and destroy humanity. When the Carroon-creature escapes from custody, Quatermass and Scotland Yard's Inspector Lomax, have just hours to track it down and prevent a catastrophe.
 * ''Directed by Val Guest. Written by Richard Landau, based on the serieal by Nigel Kneale.

It's coming for YOU from Space to wipe all living things from the face of the Earth! CAN IT BE STOPPED? (taglines)

Bernard Quatermass

 * There's no room for personal feelings in science, Judith!

Inspector Lomax

 * Nobody ever wins a cold war.

Taglines

 * Beware of "THE CREEPING UNKNOWN!"
 * It's coming for YOU from Space to wipe all living things from the face of the Earth! CAN IT BE STOPPED?
 * You Can't Escape It!
 * Nothing Can Destroy It!
 * All Earth Stands Helpless! Spawned in the depths of outer space—a monster so horrible, so vicious, so incredible—even when you see it you won't believe it could be!
 * It creeps, it crawls, it kills!

Cast

 * Brian Donlevy — Bernard Quatermass
 * Jack Warner — Inspector Lomax
 * Margia Dean — Mrs. Judith Carroon
 * Richard Wordsworth — Victor Carroon