Star and Marco attend Sensei's 30th Birthday party, where they encounter a party magician named Preston Change-O. After witnessing Preston's tricks and seeing how they have a strange effect on people, Star sets out to prove that he's a real magician.
Tropes:
- Ambiguously Evil: Whether Preston is being malicious with his joy-sucking is never made clear. He claims that it's fairly harmless, and the only reason it had such an effect on Jeremy Birnbaum is because "[he] barely had any joy to begin with".
- Emotion Eater: Preston turns out to be a "joy-sucker", feeding off the happiness of people who are impressed by his magic tricks.
- Fantastic Fruits and Vegetables: Star mentions a fruit that grows on Mewni called "oggberry". When she learns they don't have them on Earth, she claims "You are really missing out!"
- Irony: Star tries to save everyone's joy by unveiling Preston's identity before he sucks it all out, but ends up ruining everybody's good time by stopping the magic show and forcing Preston to reveal that he's not using real magic.
- Lame Pun Reaction: Star laughs awkwardly when Marco jokes that Sensei's bike-riding tricks are "sensei-sional".
- Magicians Are Wizards: Star is convinced Preston is a real magician. The truth is worse; he's some kind of monster who feeds off happiness.
- Mic Drop: Sensei does one after explaining how Star ruined the magic act.
- Nice Job Breaking It, Hero: Star forcing Preston to explain how his magic tricks work did more to make people miserable than his joy-sucking ever did.
- Special Guest: "Weird Al" Yankovic provides the voice of Preston Change-O.
- Trunk Shot: After Sensei threw Preston into his car's trunk.
