Feral Mickey is a monster originally found in the Disney animated short, "Runaway Brain." He is most prominently featured in the first Disney Villains War, re-imagined as an amalgamation of Mickey Mouse and the soul of Scar.
Disney Villains War
Earlier in the Disney Villains War, Scar perished to McLeach. However, David Xanatos and the Mad Doctor join forces in order to bond the soul of Scar to Mickey Mouse, whom they have captured. The operation is successful, and Feral Mickey is born.
A-Hunting It Will Go
The Mad Doctor decides to test Feral Mickey on a little hunting spree. The monster soon catches sight of two little pigs being chased by the Big Bad Wolf. Wanting to eat the pigs himself, Feral Mickey attacks. The wolf's powerful breath does not deter the rabid mouse. The Big Bad Wolf only manages to turn Feral Mickey away through using his sheer size. However, this same intimidation traps the Big Bad Wolf in a cleverly placed trapdoor. Feral Mickey then gets the opportunity to dine on the pigs as the Mad Doctor dissects his opponent.
Back to Normal
Feral Mickey later catches sight of Negaduck, one of Xanatos's rivals. Negaduck wisely avoids a direct confrontation and flees Feral Mickey's swipes. He then leads Feral Mickey up a drain pipe surrounded by electrical wires. With one well-placed banana peel, the mallard sends Feral Mickey into the power lines, separating Scar's soul from Mickey's body and ending the menace of Feral Mickey.
Disney vs Marvel Villains War Part 2
In the finale of the Marvel Disney Villains War, Mickey fought against Chernabog who was getting ready to unleash his spirit army upon the world like last time. Although neither one was able to destroy the other, Mickey suddenly remembered his time as Julius when Scar possessed him, and realized that becoming Julius again through Chernabog's possession would be the only way to stop the demon. So, Mickey set up a large explosion which fused the two warriors together, creating Julius and freeing Avalanche from Chernabog's control. Unfortunately, the two ended up stuck in Limbo, where Dormammu's champion, Carnage, was waiting for them.