A giant brain eating crab monster, that cannot be harmed by any weapon and communicates in the voices of its victims, and with plans of world domination. Just another one of those "Nature Mutated By Radiation" movies. This is a funny movie now, but is just another in a long line of movies playing on the fears of its time. The fx are cheesy (but probably state of the art in 1957), the giant crabs especially, with their human eyes.
The final demise of the creature is fairly typical. Definately one for those of us who love cheesy horror/sci-fi.