Duel! Ataru vs. Ataru

Urusei Yatsura – Season 1

Ataru eats a lollipop Lum gave him and gets a mouth burn. Running off, he finds Cherry and a weird melon, which Ataru eats to cool his mouth. The melon causes Ataru to split into two Ataru's, one polite and the other casual. The two continue to fight all day.