Superman III (1983) For the third installment , Ilya Salkind wrote a treatment that expanded the film s scope to a cosmic scale , introducing the villains Brainiac and Mr. Mxyzptlk , as well as Supergirl. The original outline featured a father-daughter relationship between Brainiac and Supergirl , and a romance between Superman and Supergirl , even though the two are cousins in the comics. Warner Bros. rejected it and created their own Superman III film that co-starred Richard Pryor as computer wizard Gus Gorman , who under the manipulation of a millionaire magnate , creates a form of Kryptonite that turns the Man of Steel into an evil self. The retooled s–cript pared Brainiac down into the film s evil “ultimate computer”. Despite the film s success , fans were disappointed with the film , in particular with Pryor s performance diluting the serious tone of the previous films , as well as controversy over the depiction of the evil Superman.