Dr. N. Zyme and Dr. Elrod Purvis engineer Viper Mutagen 368, a regenerative growth formula. Zyme imagines the benefits of the mutagen to mankind and tells Purvis he could not have done it without him. Purvis is uncaring, and only wants to sell the mutagen to the highest bidder and become rich. Zyme leaves the lab and Purvis steals the mutagen and its research for himself, only to be discovered by Zyme and pursued into the building's stairwell. Purvis trips down the stairs and becomes covered in the growth formula. He then collapses, supposedly dead and is taken to the morgue. Dr. Zyme discovers that the mutagen is ineffective and mutates its host into an evil monstrosity. Purvis is mutated by the formula and becomes Dr. Viper, taking his name from the mutagen itself. He then proceeds to apply the mutagen to mosquitos and honey bees to attack those responsible for his mutation.
Elenco: Charlie Adler , Gary Owens , Tress MacNeille , Candi Milo , Jim Cummings , Lori Alan .