Calvin and Hobbes by Bill Watterson for August 16, 1988
Dad: Look at this bathroom! What on earth were you doing?! Calvin: Nothing, Dad! I was just in here looking for some dental floss, when plooie! The faucet handle blows sky high all by itselr! It...it...uh... What I mean is, Hobbes was fooling around with your tools. I tried to stop him, but he wouldn't listen, and sure enough he went and...and... Dad: One more try. Calvin: Aliens, Dad! Big, evil, bug-eyed monsters from Pluto! The did it, and made me swear not to tell!