Film: Attack of the Crab Monsters (1957)
Height/Weight: As big as 3 bull elephants side by side.
Summary: Never clean up after the mess of previous explorers, because there's a good chance that whatever killed them will kill again. In this case, two telepathic giant mutant crabs not willing to stick around their home for long.
History: As per the norm, radiation was the reason for some regular Dungeness crabs turning into monsters. However, it also gave them the ability to absorb the minds of their victims and acquire their intelligence. Soon the crabs began to sink their own island with their very presence, but they could care less, as they planned to leave their home in order to storm civilization.
Notable Kills: It's almost always about luring their victims with the voices of their previous prey.
Final Fate: The first crab monster is impaled by a stalactite while the other is killed by a falling electrical tower.
Powers/Abilities: The trump card of the crabs is their ability to absorb the intelligence of their victims and add it to their own. This way they can telepathically communicate with humans using the voices of their prey. They are also impervious to bullets.
Weakness: Electricity is the only thing that can penetrate their hides aside from really blunt objects.
Scariness Factor: 3.5-Despite their terrifying power, the utter stiffness of the monster props kills most of the tension they might have been trying to enforce.
Trivia: -At the time, this film was considered Roger Corman's most successful endeavor. He was convinced that it was mostly because of the bonkers title.
-The largest crab in the world is the Japanese spider crab, with a foot-long leg span from claw to claw.