Black Friday

A 1940 science fiction horror gangster film starring Boris Karloff and Bela Lugosi tells the story of Professor George Kingsley, who is accidentally run down by gangster Red Cannon and left with brain damage. To save his life, Kingsley's friend Dr. Ernest Sovac performs a highly unethical operation to replace his brain with that of Cannon, creating a dual personality. As Cannon begins to manifest in the Kingsley persona, Sovac uses hypnosis to awaken the Cannon persona, leading to a cat-and-mouse game between Cannon and his former gang members. Ultimately, Cannon's murder at the hands of Sovac leads to the downfall of both men, with the sinister doctor facing execution for his crime.