Cheap and cheerful, Behemoth the Sea Monster borrows from the American giant monster films of the 1950s, especially director Eugène Lourié's earlier influential classic The Beast from 20,000 Fathoms. It's worth a look for the novelty of the London setting, the appearance of Hammer Horror regular André Morell, and the final FX work by King Kong legend Willis O'Brien.
American scientist Steve Karnes (Gene Evans) is giving a speech to British scientists about marine life and the dangers by nuclear testing. Later, he learns of thousands of lifeless fish washed ashore on the Cornish coast and the death of a fisherman from radiation burns. Teaming up with Professor James Bickford (Morell) to investigate, the pair find a passenger ship destroyed, with the loss of all on board, while tests show the dead fish were full of radioactive contamination. Karnes begins to suspect the creature the fisherman described seeing is a beast mutated by nuclear testing, with a desire to come back to London.
In the first ten minutes we get all the tropes you expect from this genre. 1) A conference of scientists with ominous warnings. 2) A bureaucrat who dismisses said warnings. 3) A pretty girl, and a hunky love interest. 4) somebody having a deadly encounter with something, linked to the opening scene, and shot from the point of view of the something. 5) The dying man muttering portentous semi coherent warnings with his dying breath. Following this comes lots of padding, occasional exposition, further deaths and possible monster sightings. Finally, the full reveal of the monster and a trail of destruction. In this respect, Behemoth the Sea Monster is no different, but it is still entertaining for the most part. There is some hokey Dr Who level rubber glove puppet special FX, some atmospheric scenes in Cornwall, and the always watchable Morell.
In fairness, the stop motion monster in the final scenes is not too bad considering the low budget, and this was the final credited work of Willis O'Brien. While he did not invent the technique, he refined and brought it to popular attention through King Kong, inspiring the likes of Ray Harryhausen.
Lourie would go on to give the monster smashing up London in the more colourful and fun Gorgo. This took the action from destroying anonymous docks and houses, to smashing London landmarks like Tower Bridge.
