[[quoteright:310:https://static.tvtropes.org/pmwiki/pub/images/attack_of_the_crab_monsters.jpeg]]

->''"Once... [[WasOnceAMan they were men]]. Now they are land crabs."''
-->-- '''Dr. Brewer'''

A 1957 SciFiHorror BMovie produced and directed by Creator/RogerCorman and released by Creator/AlliedArtists. The cast includes Richard Garland, Pamela Duncan, and Russell Johnson.

A group of scientists land on a remote Pacific island after it was irradiated in the Bikini Atoll nuclear tests, in search of a previous group who disappeared while studying the radiation's effects on its ecosystem. It turns out that they were [[IAmAHumanitarian eaten]] by [[GiantEnemyCrab Giant Mutant Land Crabs]](!), which 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. With the humans cornered and on the run, the crabs close in for the kill...

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!!This work provides examples of:

* AssimilationPlot: The Crabs do this whenever they eat someone. Absorbing them into their [[HiveMind collective consciousness]] of each individual crab.
* BMovie: The former trope image.
* EatBrainForMemories: When the Crabs eat someone's brains, that person's consciousness is assimilated into their hivemind and their memories are at the Crabs' disposal.
* ExactlyWhatItSaysOnTheTin: It's a film about giant crabs attacking people.
%%* TheFifties
* GiantEnemyCrab: [[NuclearMutant Giant mutant crabs]] who attack people on an island.
* HeroicSacrifice: Hank Chapman destroys the final crab by crashing an antenna on it, frying them both.
* IslandOfMystery: The island the crabs are on.
* NighInvulnerable: 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.
* OffWithHisHead: One of the seamen is decapitated by a crab when he falls from a boat.
* PlayingWithFire: The Crabs can produce "arcs of heat" which they use to detonate dynamite.
* TouchOfTheMonster: The poster features a crab monster holding a distressed female in peril, which [[CoversAlwaysLie doesn't occur in the film at all]].
* VoiceChangeling: 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.
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