Attack of the Crab Monsters (1957)

A group of scientists embark on a journey to a mysterious sinking island to investigate the strange disappearance of a previous team. Soon the ill-fated crew began to hear voices, first of the missing scientists and then of members of their own expedition. It couldn't be giant, intelligent crab monsters, could it? Naw, that's way too far fetched!
B&W | Allied Artists

The Giant Behemoth (1959)

Bright lights have been sighted. Heaps of dead fish are washing up on the shore. A fisherman is killed by severe burns from an unknown source. What could it all mean? The Giant Behemoth, of course! An enormous sea monster, later revealed to be a living specimen of the long extinct Paleosaurus harries the coast and the Thames River area in England. And, to make things even better, this beasty is radioactive!
B&W | Allied Artists

Tarantula! (1955)

A scientist, driven by the benevolent desire to solve world hunger develops a nutrient that causes abnormally fast growth in animals. During a fire in the good Doctor's laboratory, a gargantuan tarantula escapes from it's enclosure and begins to terrorize the surrounding countryside.
B&W | Universal International