Smashy Smashy

At the university there is an art exhibit that is a large cube with 2 windows. One has glass in it, one doesn't.
Reegan goes to stick his head into the window.
SMASH!
Reegan takes a quick step backwards with a puzzled and confused look on his face.
We leave.

Reegan: "I can't believe that just happened."
Me: "It smashed pretty good, you must have hit it hard."
Reegan: "Yeah. I can feel the impact point but my head isn't bleeding."
*runs his fingers into his hair to check his scalp*
"Oh, yes it is"