My Gym Partner's a Monkey (2005)

S1E10 Shiny Thing

Jake stumbles upon a dazzling diamond doorknob and quickly realizes its magical influence when all his classmates, except for Adam, become mesmerized by its sparkle. As Jake's fixation on his own rear escalates, he inadvertently leads his peers to focus solely on studying monkey butts, much to the amusement and confusion of everyone around them.