The monster admires the Super Teenage Power Pogo Stick Telly has just received from his Uncle Charlie. Telly is impressed with how well she can ride it, especially considering how badly his attempts went. She assures him with practice he'd be able to ride it. Later, Telly catches up with her so she can give him some lessons on it. After watching him take more tumbles on it, she concludes it's too powerful for him at his current age. In gratitude for helping him see the light, Telly allows her to borrow it whenever she wants and even teaches her a trick with his original pogo stick.
Her voice is reminiscent of that of Annette Funicello. The character is not given a name in the episode, but is consistently referred to as "Teenage Monster."