The Buffy episode in which Jonathan makes himself famous by magic is “Superstar.”
“Superstar” is the 17th episode of Buffy the Vampire Slayer’s fourth season, first broadcast on April 4, 2000. Jonathan Levinson, previously an awkward and marginal student, casts an augmentation spell that makes everyone perceive him as extraordinary. In the altered reality, he is famous, admired, talented, heroic, and apparently responsible for many of the accomplishments normally associated with Buffy and her friends.
The spell does not simply improve Jonathan’s life; it reshapes reality around him. Its supernatural side effect is a powerful demon that balances the benefits Jonathan receives. Buffy and the Scoobies gradually realize that the world’s praise of Jonathan is artificial and that destroying the demon will reverse the spell.
The episode is often confused with “Storyteller,” another Jonathan-centered episode from season seven, or “The Zeppo,” which gives Xander an alternate perspective on a major crisis. “Him” is a season seven episode about a magical football jacket, not Jonathan’s rise to fame. “Superstar” is also notable for altering the opening credits to feature Jonathan prominently.