Cow and Chicken (1997)

Season 3: Episode 5

Mom and Dad go out of town, leaving Cow as the babysitter, because she's the biggest, and not the oldest. Pretty soon, Chicken is at the mercy of his sister's babysitting technique: eating marshmallow soup for supper, doing homework with Crabs the Warthog doll, Piles the Beaver doll, and Manure the Bear doll, taking a bath and being scrubbed with dishsoap, and wearing diapers.