As soon as Hip and Hop get up and start running away from Koopa after their volcano erupts in the school, Hop's head is brown (same color as his skin).
The song "Rockin' The High School" is misquoted, such as the scene took place in elementary school, but the song mentions only high school.
In this episode, characters like Ugtar and King Koopa mistakenly refer to Hip and Hop Koopa as lizards. The Koopas from the franchise are tortoises, which are not members of the lizard family.