Calvin and Hobbes by Bill Watterson for October 23, 1988
Transcript:
Calvin: I feel a big sneeze welling up...which is always a sure sign that i'm not carrying a handkerchief. AH...AH...AH...CHOOOO!! Mom: Mom, i sneezed and blew my head off! Calvin: Pull your shirt down, Calvin. You're not fooling anyone. Calvin: Mom would be a lot more fun if she was a little more gullible.
Yes, you have seen this one before: http://www.gocomics.com/calvinandhobbes/1988/09/11