A group of scientists travel to a remote island to study the effects of nuclear weapons tests, only to get stranded when their airplane mysteriously explodes. The team soon discovers that the tests have given rise to crabs mutated into intelligent, impervious, telepathic giants intent on increasing their numbers by breeding, then travelling to populated areas to feed, and which do not intend to be stopped by their discoverers.
Richard Garland
as Dale Drewer
Pamela Duncan
as Dr. Martha 'Marti' Hunter
Russell Johnson
as Hank Chapman
Leslie Bradley
as Dr. Karl Weigand
Mel Welles
as Jules Deveroux
Richard H. Cutting
as Dr. James Carson
Beach Dickerson
as Seaman Ron Fellows
Tony Miller
as Seaman Jack Sommers
Ed Nelson
as Ensign Quinlan
Charles B. Griffith
as Seaman Mac, wears sunglasses
Maitland Stuart
as Diving-double for male cast
Robin Riley
as Diving-double for Pamela Duncan
