USA - 1955 - 1H19 – VOST Directed by  Robert Gordon With Kenneth Tobey, Faith Domergue, Donald Curtis

During its inaugural voyage, a nuclear submarine is pursued by a gigantic "thing" that attempts to pull it towards the sea bottom. The sub escapes with a piece of its pursuer, and an investigation is opened on return. It takes a beautiful biologist to discover the truth. The sub was attacked by a giant octopus, whose behaviour has been altered by atomic testing, and it becomes clear that its searching for food will put the western coast of the United States in peril.