Professor Egg is an alternate version of Dr. Robotnik from the Zone of Mobius-Seventeen. As a mask-wearing supervillain, he does battle with his universe's Sonic the Hedgehog, aka Stealth the Hedgehog. His zone was destroyed during Master Mogul's rampage through the Cosmic Interstate, but was restored by Titan Tails. (StH: #149, #150)
- Professor Egg is a parody of Marvel Comics' Green Goblin.