Though I'm still partial to NOT OF THIS EARTH, (which played on a double bill with Crab) and IT CONQUERED THE WORLD, this is still lots of fun and competently made on a very low-budget (just 70,000 dollars) by B-movie master Roger Corman. The running time is a breezy 62 minutes. After H Bombs have been dropped on a small island, a varied team of researchers and military men show up to both research the effects of radiation fallout on animals, soil and native vegetation, as well as search for people from a previous scientific expedition that have turned up missing. After a member of their party is mysteriously decapitated, the airplane they arrived in explodes and they find themselves stranded, our heroes discover they're not alone on the island, as a slew of gigantic super-intelligent killer crabs with peculiar abilities come crawling out of the caves looking for food. To make matters even worse, because the crabs put off so much heat and are digging elaborated tunnel systems underground, frequent landslides and sink holes are quickly starting to shrink the island.
Not content giving us another standard monster-movie opus, screenwriter Charles B. Griffith (also the associate producer) has added a few clever variations on the formula to make this a little more interesting than usual. One of the most novel ideas is that the crabs are able to absorb the minds and memories of their victims by eating their brains, and then can use the voice of their victims to lure new people into their clutches. Having the island rapidly shrinking throughout the film was also an ingenious way of increasing tension without increasing the budget. The crab monster design actually isn't too bad either, and completely charming, besides. And the cast is full of familiar faces from other Corman flicks, with Richard Garland and Pamela Duncan (both from the undervalued THE UNDEAD) starring as engaged biologists, and Leslie Bradley and Mel Welles both giving fun performances as veteran scientists. Also on board are Russell Johnson (who'd be stranded on a desert isle again a few years later as "The Professor" on Gilligan's Island), Ed Nelson, Beach Dickerson and Griffith himself is a small cameo.