Scoring a UCM hat trick

Of the Universal Classic Monsters Big Three, Bela Lugosi has starred in two movies and one serial featured on MST3K, while Lon Chaney Jr. has appeared in one movie and one serial. Yet Boris Karloff has yet to appear in an MST3K movie (assuming he’s not in one of the as yet unnamed movies for Season 13). So what movies featuring him do you think should be screened on MST3K? I offer The Crimson Cult, which as a bonus also features Christopher Lee.