Peanuts by Charles Schulz for January 28, 2001
Snoopy & Woodstock start off at the top of a hill on a sled Snoopy: (Hang on!) (Here we go!) They start sliding down the hill and bump on something that makes them flip Woodstock: *looking around franticly* Snoopy: Oh, no! I can't believe it! Woodstock has lost his retainer!