There has been an expedition to this hitherto unknown Pacific atoll before, but nobody knows what happened to them - they simply disappeared. As the area is being used for atomic bomb tests, it is going through some measure of upheaval and another expedition has been sent out to investigate the effect the testing has had on the local wildlife and landscape. After fresh bombing causes a tidal wave, the party led by Dale Drewer (Richard Garland), consisting of biologists, botanists and sailors, arrive on one island. But not only is it unstable, it has unwelcoming inhabitants as well...
Somebody tell me Guy N. Smith saw this film, he must have done. Attack of the Crab Monsters was one of the B movies Roger Corman produced and directed from a script by Charles B. Griffith (who also appears as a sailor), but unlike the writer's more celebrated works, such as Little Shop of Horrors or A Bucket of Blood, this was altogether more serious in tone. Not that audiences haven't found the antics on display here to be fairly campy, especially when you see the monsters, but it could still be taken on a more sober level than that.
Using as much stock footage as possible appears to be the main endeavour for Corman here in between shooting his actors on the beach (where they have to shout to be heard over the surf) or on a set depicting their base of operations. The stock footage comes into play whenever anything related to the atomic bombs is seen, so as with about fifty percent of science fiction movies of the fifties there are those shots of massive A-bomb explosions (or are they H-bombs?) that open the proceedings, and the geological effects are represented by huge waves crashing on the shore or landslides.
Yes, landslides, for the characters are on an incredible shrinking island due to the extensive earth tremors the site is suffering. Simple, you think, all they need do is call for help on the radio, but nope, they can only pick up local commercial stations. Well how did they get there in the first place? By seaplane, so why don't they use that to escape? Bit of a snag there, the seaplane has blown up as it was taking off, killing the pilot, so Dale and his intrepid band are as good as trapped. Which would be bad enough on a crumbling atoll, but even worse when you're sharing it with the crab monsters of the title.
Ah, those crab monsters. Well, there's really only one that represents them all, and an ambitiously large puppet it is too with its waving claws and mad, staring eyes (so what if actual crabs don't have mad, staring eyes?). To keep this from being too routine, Griffith had the brainwave to make the creatures telepathic, so when they devour their victims they adopt their personalities and can speak with their voices, projected into the minds of their next potential victims. It can be highly amusing to hear the unlucky actors whose characters have been bumped off dubbed over the ungainly monster, especially when it's Mel Welles doing the voiceover. But for all the affection that this is held in, it's pretty minor Corman and the low budget is painfully obvious. Music by Ronald Stein.