"Plan 9" may be the best-known bad film of all time, but "Devil Monster" is an infinitely worse film. Much of the movie is clearly stock footage taken from a much earlier film. Ludicrous narration tries to tie it all together, but much of this grade-Z shlockfest makes no sense. The big finale fight scene, in which a sailor grapples with the Devil Monster, has the cheapest special effects you have ever seen. A man splashing around in water is superimposed over footage of manta ray. This movie is not for everybody, but lovers of trashy cinema may find it amusing.