Screaming Doctor Berserk
A mad doctor, who employed an Igor who later helped Jeremy Clockson build a Glass Clock in Thief of Time. According to Igor, he later died of blood poisoning caused by a rusty pitchfork. In a bad case of mistaken identity, Crazed Baron Haha died when an angry mob mistook him for Screaming Doctor Berserk. Evidence of his doctorate has yet to be revealed.
The Roundworld reference to both Screaming Doctor Berserk and Crazed Baron Haha is to Doctor Frankenstein, a mad scientist who reanimated a dead body in a hit movie of 1931.