 The film was produced by Ted Lloyd, directed by Eugène Lourié, and stars Gene Evans and André Morell.The screenplay was written by blacklisted author Daniel James (under the name "Daniel Hyatt") with director Lourié.Originally a story about an amorphous blob of radiation, the script was changed at the distributor's insistence to a pastiche of "The Beast from 20,000 Fathoms" (1953), though elements of the original concept remain in the early parts of the film and in the "nuclear-breathing" power of the titular monster.