Lugosi) and becoming infected by radiation (Radium X) in a meteor of the nebula Andromeda, Karloff was transformed into a murdering, radiation-poisoned megalomaniac as he hunted down his enemies and projected death rays at them from his eyes (glaring from under a soft felt hat)
Tod Browning's off-beat The Devil Doll (1936) - with Devil's Island escapee and scientist Paul Lavond (Lionel Barrymore), disguised as a macabre elderly woman ("Madame Mandelip"), vengefully terrorizing his enemies by creating shrunken "devil dolls" to seek out his revenge; with landmark special effects, and Maureen O'Sullivan in a supporting role as Lavond's daughter
Ernest Schoedsack's and Paramount's Dr. Cyclops (1940) - the first Technicolor horror/sci-fi film since The Mystery of the Wax Museum (1933), with Albert Dekker as sadistic, bald, bespectacled mad scientist Dr.Thorkel shrinking his victims in a remote Peruvian jungle setting; the film received an Academy Award nomination for its Visual Effects
The Monster and the Girl (1941) - another Paramount "B" horror/sci-fi film from director Stuart Heisler, about eccentric mad scientist Dr. Parry (George Zucco) who transplanted the brain of a wrongly-accused and executed murderer into a murderous gorilla, who then went on a rampage to seek revenge
director George Sherman's The Lady and the Monster (1944) - the first film version of the classic tale Donovan's Brain by Curt Siodmak [remade in 1954], in which the throbbing, telepathic brain of a dead and unscrupulous industrialist/maniac named James Donovan was kept alive by enthusiastic mad scientist/Prof. Franz Mueller (Erich von Stroheim)
Escapist Serials of the 30s: Flash Gordon and Buck Rogers

In