Oh i think everyone has a story here, when i was still white belt my sensei told me about this one loco dude who came to the dojo, and insisted fighting with the black belts, on his second or third day he decided to pair up with a 2nd dan black belt lady, who was half his height and weight, he decided itll be a good idea to go full out, and pin her against the wall and broke her ribs, in such a way that the bone stuck through her breast :|. Of course she was taken to the hospital to get treated, but all the other black belts kept him there forcefully when he saw he caused serious trouble. He started off fighting one of my senseis and had to go through 10 of them untill he reached our head instructor (whos one of the highest ranked karateka in Africa), who and i quote "took care of him". I would rather not wanna know the details, but he never came back.
Be the change you wish to see in the world