Buddy Love

Buddy Love is Sherman Klump's Alter Ego and the main antagonist of the films. He first started out as the result of Sherman inventing a formula designed for the user to shed weight instantly. At first Buddy was merely Sherman, only thinner, but due to Sherman hiding his identity in combination with the extreme rise of testosterone; Buddy became a separate personality all his own. Buddy behaves in a cruel and overly assertive manner, a complete opposite of the kind-hearted, loving and friendly Sherman. In the first film, he attempts to destroy Sherman for good while in the second film, he attempts to capitalize on Sherman's youth formula and become rich off it.

He eventually becomes a separate entity from Sherman in The Nutty Professor II when he is extracted from his DNA after Sherman begins acting in the same cruel manner as Buddy, causing him to upset Cletus Klump and Denise Gaines with his actions. After the extraction, Buddy accidentally combines with the DNA of Buster, a Basset Hound who caused a loose fur to to bring him back to life but also causing him to develop dog-like qualities to his personality. Buddy being split from Sherman causes the latter's brain cells to deteriorate. Sherman reduces Buddy to a baby and then a gel-like substance with an upgraded version of his youth formula in order to regain his intelligence. As Buddy evaporates into a fountain, Denise's tears reconstitute Buddy's genetic makeup and Sherman drinks the water, thus restoring his brain functions.