Calvin and Hobbes by Bill Watterson for December 26, 1990
Transcript:
Calvin: Dear Grandma, thank you for the nice box of crayons you sent me for Christmas. Hobbes: This is prompt. Calvin: Oh yeah. I always send grandma a thank-you note right away. ...Ever since she sent me that empty box with the sarcastic note saying she was just checking to see if the postal service was still working.
When was Calvin’s grandmother seen in the strip?