A radiation leak causes crabs to mutate. One of them becomes a giant 8 foot crab, but most of them become ... normal looking crabs. The normal crabs do nasty things like burn down the trailer of a banjo player. Large bunches of normal crabs scuttling around are not very threatening. This film doesn't really work on any level. Veteran actors Robert Lansing and Barry Nelson are here, but unfortunately Steve Hanks is the nominal star and he's such a terrible actor that he can't manage to do normal tasks like pouring a cup of coffee without looking stiff and awkward.