Dr. Cerebral (Dwayne Hill) is a strange being, consisting of a teeny brain with a face floating in a glass dome with mechanical legs and arms who yearns to control the universe, and eliminate inefficient and unsanitary organic life forms in the process. The self-proclaimed worst genius in the galaxy, he is always trying to devise ways to destroy other stupid beings and prove himself the stupidest.
First he invented a device called The Stupifactor Ray, which, when used to zap people, made them act stupid, thereby making him seem smarter. Then he tried to create a giant robot monster made from stolen data from some of the galaxy’s best programmed robots, including B-1 and X-5; Dr. Cerebral himself would serve as the monster’s brain, this plan almost destroyed B-1 and X-5. In the episode "Oy, Robot", he obtained a new robot and used it to convert organic lifeforms into robots, believing that they are superior and cleaner. He even transformed Sparky into a robot, but Betty managed to stop Cerebral and turn everyone back to normal.
In its sequel "The Gazundheit Factor", he created an organic life form called "The Gloob" that can eat other life forms, but it was constantly trying to eat Dr. Cerebral instead, later in the episode, Betty and her crew and Dr. Cerebral work together to stop "The Gloob". In the episode's conclusion, he says that he should have known better than to trust an organic life form to do his evil bidding ("Ugh! I should have known better than to trust an organic life form to do my evil bidding") when both Dr. Cerebral and "The Gloob" were arrested by Betty and her crew (Dr. Cerebral and "The Gloob" became cellmates). He later returned in the season 3 episode "Rodeo Robots" in which he used a remote control from Crushton to take control of Robo-Betty and use her to try and destroy the Galactic Guardians.
Cerebral returns in the episode "Cosmic Comicon", in which he is offended by Regeena, who is dressed as "Dr. Brainy", his counterpart in Noah's Atomic Chick comic book, and goes after Regeena to steal her toy version of a part needed for his doomsday device (unaware that he himself has the working version and Regeena has the lookalike). Cerebral and Regeena manage to switch their parts, while Betty takes the opportunity to leave with X-5 to lead a preemptive strike on Cerebral while Cerebral has Regeena's knockoff. However, Cerebral quickly realizes this, and returns to Earth to steal his original back from Regeena. Betty takes the opportunity to take her role as Atomic Chick and disarm Dr. Cerebral; Cerebral is later beaten up by the legions of convention-goers.