Doctor Frankenollie is a mad scientist who attempted to switch Mickey's brain with that of his giant monster Julius in Runaway Brain. His name is a play on two famous Disney animators, Frank Thomas and Ollie Johnston. He appears to also have been inspired by the earlier Mickey Mouse villains Professors Ecks, Doublex, and Triplex.
Role in the short
Frankenollie puts an ad in the newspaper promising to pay his employer $999 and 99 cents. Mickey answers the ad and heads over to the address. Mickey is sucked into an underground laboratory and captured. Frankenollie then informs Mickey of his sadistic plan; to switch his brain with that of his monster Julius. During the brain switch, he attaches helmets to their heads and activates a switch while laughing manically causing a large explosion. Mickey awakes to find himself in Julius' body and finds a charred Frankenollie and tells him to change him back but it is too late as the doctor was killed in the explosion and disintegrates in Mickey's hands.
Dr. Frankenollie is central to a line of action figures sold in the Disney Theme Parks, Disney "TRONICS" GvE, where he has built a series of giant robots based on various Disney characters, heroes and villains, to fight each other for his own amusement.