Trailer
Cast
Donald Curtis
Maj. Huglin
Thomas Browne Henry
Vice Adm. Enright
Frank Wilcox
Alfred Cassidy, Alfred Cassidy (uncredited)
Joan Taylor
Carol Marvin
Morris Ankrum
Brig. Gen. John Hanley
John Zaremba
Prof. Kanter
Forbes Murray
Military Officer at Experiment, Military Officer at Experiment (uncredited)
Arthur Tovey
Officer/Civilian at Military Conference
Dale Van Sickel
Man Crushed Beneath Wall (uncredited)
Paul Frees
Alien (voice), Alien (voice) (uncredited)
Sol Murgi
Plane Passenger (uncredited)
Charles Evans
Dr. Alberts (uncredited)
Larry J. Blake
Motorcycle cop
Clark Howat
Sgt. Nash (uncredited)
Mike Ragan
Tank Commander (uncredited)
William Woodson
Narrator (voice) (uncredited)
Harry Lauter
Cutting - Generator Technician (uncredited)
Hugh Marlowe
Dr. Russell A. Marvin
Grandon Rhodes
Gen. Edmunds