My names Jim, but call me X

Jim decided he wanted to go by “X” ( as in the letter x),
People would ask “Jim, why X?”,
He’d answer “Shut up!” and grab them by the head.
He then proceeded to draw a big, fat X in permanent marker
On their forehead.
Then he’d say, in a threatening tone “That’s why! Eat it!”
He’d been doing it since he was a child.