When you hurt yourself so badly that your hair falls out or causes such psychological stress that you go bald or have to have your head shaved.
Yea, I cracked my head open and they had to shave my hair off... talk about an Owie Mendel!
There were too many germs on my head so I had to go Owie Mendel on myself.
That test was so hard that I went Owie Mendel.