Julius is a giant hulking Frankenstein's monster-like look-alike of Pete that was created by Doctor Frankenollie and had Mickey's brain for a short time and the main antagonist of the 1995 short film Runaway Brain.
Julius is unleashed from his lair under Frankenollie's lab to switch brains with Mickey Mouse. The experiment was done successfully although it killed Frankenollie in the process. However, Julius and Mickey not only switched brains, but bodies as well. In Mickey's body, Julius was able to view Mickey's wallet where he finds a picture of Mickey and Minnie. He develops feelings for her and rushes out to find her. He spots her at a shopping store and enters to proclaim his love. Unfortunately, Minnie thinks it's Mickey she's talking to and when the real Mickey in Julius' body enters to save her, she attacks him. Mickey is able to explain and battles Julius while Minnie is safe on top of a skyscraper. Mickey and Julius end up being electrocuted on cable wires, switching back in the process. Now that Julius is in his rightful body, he has a better chance of destroying Mickey and getting Minnie. Still, Mickey manages to free Minnie from his grasp. He is accidentally knocked off the building by Minnie but is pulled up repeatedly like a yo-yo as he is tied to a rope attached to a moving Hawaiian girl's arm on a billboard. In the end, Mickey and Minnie use Julius to pull a raft to Hawaii for vacation.
- Jim Cummings