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Attack of the Crab Monsters is a 1957 American black-and-white science fiction film, written by Charles B. Griffith and produced and directed by Roger Corman via Los Altos Productions, on contract for distribution by Allied Artists Pictures Corporation. The plot follows a scientific expedition trapped on a remote island inhabited by atomically mutated giant crabs. It was distributed as the main feature on a programmed double bill with Corman’s Not of This Earth.
A group of scientists land on a remote island in the Pacific to search for a previous expedition that disappeared and to continue research about the effects of radiation from the Bikini Atoll nuclear tests on the island’s plant and sea life. They learn to their horror that the earlier group of scientists have been eaten by mutated giant crabs that have gained intelligence by absorbing the minds of their victims. Members of the current expedition are systematically attacked and killed by the crabs, which are invulnerable to most weaponry because of the mutation in their cell structure. Finally, they discover the crabs are the cause of the earthquakes and landslides that are destroying the island, and begin thinking of a way to stop the crab monsters from reproducing. After barely escaping from a laboratory that was close to collapsing, the remaining trio witness one of the giant crabs for the first time. This was Hoolar, The Giant Crab, played by David Arvedon. Hoolar vows to swim to the mainland to eat more people. At last, one of the three sacrifices his life to kill Hoolar. The film ends with the survivors embracing each other.
Text source Wikipedia.