A group of scientists land on a remote pacific isle after it was irradiated, in search of a previous group who went missing studying the effects of the radiation from the Bikini Atoll tests on the local ecosystem. Turns out they were eaten by Giant Mutant Land Crabs (!) who have absorbed their intelligences by eating their brains. The crabs then go about killing the humans one by one. Once the humans learn of their weakness, the crabs step up their plan to hunt them down, using dynamite to destroy the island bit by bit. Cornered and on the run, the crabs close in for the kill...
This work provides examples of:
- Assimilation Plot: The Crabs do this whenever they eat someone. Absorbing them into their collective consciousness of each individual crab.
- B-Movie: The former trope image.
- Heroic Sacrifice: Hank Chapman destroys the final crab by crashing an antenna on it, frying them both.
- I Love Nuclear Power: Source of the mutant land crabs, making them Nuclear Nasties.
- Island of Mystery: The island the crabs are on.
- Nigh Invulnerable: The crabs are immune to all physical attacks—which just pass through them as if they were globs of mercury. Elecriticy, however, kills them instantly.
- Off with His Head!: One of the seamen is decapitated by a crab when he falls from a boat.
- Playing with Fire: The Crabs can produce "arcs of heat" which they use to detonate dynamite.
- Touch of the Monster: The poster features a crab monster holding a distressed female in peril, which doesn't occur in the film at all.
- Voice Changeling: The crabs can mimic the voice of any person they hear by vibrating any nearby metal. This creates an echo to the voice that serves as a haunting tip off.