Before he was known as Professor Monkeyhead, he was simply a mad scientist who helped perfect the Soviet Super-Ape program; this program created The Leftist Gorilla.
The mad scientist then worked on training monkeys to drive miniature trucks in order to have monkeys become a slave workforce for humanity.
Susan and Ed, his research assistants, objected to the immoral experiments and the scientist's drinking problem. They warned him that his drinking jeopardized the experiemnt and his calculations were incorrect.
Despite the warnings, the experiment proceeded. An explosion occured, the toxic chemicals and radioactive isotopes mutated Susan into the animalistic Monkey Baby, Ed into the super-powered Truckstop and the mad scientist was mutated into Professor Monkeyhead. Lethargic Lad #8
Despite being villains, Professor Monkeyhead often finds himself in conflict with Evil Smiley Face Guy and the Part-Time-Lethargic-Lad-Revenge-Squad.