The Brain from Planet Arous (1957)

An evil alien brain seeks to conquer Earth by seizing control of an atomic scientist's body. Meanwhile, a benevolent alien brain occupies the scientist's loyal dog, biding its time to thwart the sinister plan. As the scientist grapples with the alien's malevolent influence, a battle of wits ensues between the two otherworldly minds. The fate of humanity hangs in the balance as the dog prepares to intervene and restore order, showcasing an unlikely alliance in this thrilling sci-fi tale of good versus evil.