8x57 - Rugrats

Angelica takes her "life-like" doll, which happens to look like Dil, to pre-school. But after one of her classmates brought a similar type of doll to show-and-tell, Angelica delayed her presentation a day, so she could switch her doll with the real thing -- Dil. But with Dil at school and her doll at Tommy's house, the Rugrats were led to believe that Dil turned into a doll because he was bad.