Calvin and Hobbes by Bill Watterson for May 21, 1987
Hobbes: Well, your hair doesn't stick up the way it used to, but at least your head's yellow again. Calvin; Thanks, Hobbes. You're a real lifesaver. I'm sorry I got so mad at you. Hobbes: Nonsense, no harm done. Calvin: Boy, wait till I show mom! Hobbes: Uh oh. Does it come off? Calvin: From now on, just keep your brainy ideas to yourself, OK?