Eric Cartman Outfit
Cartman from South Park's outfit can be seen briefly in Season 2.
In episode 9-A of Season 2 one of the Powerpuff Girls classmates, Mike has created an evil imaginary friend named, ‘Patches’. After Mike begins to get taunted by the other children for “talking to himself” Patches becomes agitated and begins to slowly terrorize the classroom eventually forcing the Powerpuff Girls to step in.
While fighting Patches all 3 of the girls are defeated in one way or another, but the easter egg comes in when Blossom is sent flying into a pile of clothes and emerges dressed in a blue winter hat, red coat and yellow gloves, just like Eric Cartman from adult comedy cartoon, South Park.