[Vigilanteman]

My daughter attended a Japanese nursery school and had a similar problem with one of the boys. It ended when she gave him a bloody nose. Her nickname after that became Kinniku Lady.

[B-Chan]

LOL. For those who don't know, there's a well-known comic book character in Japan called Kinnikuman ("Muscleman"), who is a sort of wrestler/strongman type superhero. The name comes from kinniku (筋肉), which means "muscle", hence the humor in calling a little girl "muscle lady".