Headbanger is a fusion of two opposing personalities into a two-headed body made up of Dr. Bender, the cantankerous mad scientist for the right half, and Fender, the surfer-like singing telegram boy, for the left half. The Fender part was responsible for the accident where they fell into the atom-smasher and got joined into one body. Bender mutated into a green creature akin to Toxie, but Fender retained his human appearance.