Ed and Susan were research assistants to a mad scientist who wanted to train monkeys to drive miniture trucks so that mankind could live in luxury while monkeys did all the work.
Ed and Susan 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 Ed into the super-powered Truckstop and Susan into the animalistic Monkey Baby. The mad scientist was mutated into Professor Monkeyhead. Lethargic Lad #8
Truckstop and Monkey Baby would go on to become members of The Beef League.