Richard Garland, Pamela Duncan, Russell Johnson, Leslie Bradley, Mel Welles, Richard H. Cutting, Beach Dickerson, Tony Miller, Ed Nelson, Charles B. Griffith, Maitland Stuart, Robin Riley
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.