Thumb's Up (S07E11)

The Rugrats engage in a game of "Follow The Leader," with Dil taking the lead. When Dil starts sucking his thumb—copying Stu after he accidentally hits his thumb with a hammer—the other kids follow suit and can't seem to stop. The adults, alarmed by what they see, panic after reading in a Lipschitz book that thumb-sucking could result in bad grades and buck teeth. Seizing the opportunity, Angelica tricks Chuckie into thinking that their thumb-sucking will turn them into ducks, creating a wave of worry among the toddlers.