The Black Gerbil
Whenever I would play around sparring with my friend's kids, usually little boys, I would adopt the Kung-fu name "The Black Gerbil". I would say things like "No one defeats the Black Gerbil!", "The Black Gerbil always triumphs!", "Come to my Exercise Wheel of Death!" and stuff like that. Being "The Black Gerbil" was sort of an alter ego of mine with these kids.