"Cool Summer" is the first segment of the twenty-third episode of The Emperor's New School.
Kuzco goes to the beach with Pacha and Chicha but he fears that the two "old people" will ruin his coolness. Yzma uses a youth potion to make herself an attractive teenager to get near Kuzco and smack him with a hammer. Through a mistake Chicha and Pacha turn into their teenage selves again. When the 18-again couple prove themselves neater than Kuzco, everything changes.