It Came From Beneath the Sea was a 1955 film based on finding of giant animals in the Pacific Ocean, Myth by sailors, and the atomic blast test durring the time. Ray Harryhausen included a Giant Octopus in the film.
In the film It Came From beneath the Sea a giant cephalopod rises from deep underwater trenches because nuclear test disturbes it and it rises in anger. the octopus probably rised from the underwater trenchs Kurl, Japan, or the Marianas Trench that are extremly near the U.S Nunclear test in the Pacific Ocean. The octopus then attackes sea vessils and eventualy makes his way to Californa were it gos to San Fransico and toples buildings breakes bridges and smashes cars and people. Eventuly the U.S government sends soldiers and kills the octopus, by stabing it's brain cranium with through the eye with a harpoon, its only true weakness.