In the Rugrats episode Touchdown Tommy when the dads are shown on the couch. Look closly and you'll see that there are chocolate stains on the wall (from Tommy's bottle.)But Tommy hasn't got his bottle yet. Oops that wasn't supposed to happen.
Mindy Doll,
If the stains were from a different time, them someone would've cleaned them up earlier, and they wouldn't be on there. But the submitter is right; there's a mess that looks like chocolate milk on the wall:
After Grandpa gets up to get the kids milk, the camera cuts to Stu, who says "Galloping Geezer--geez!" On the wall behind him is (you guessed it) chocolate milk!