Bart trades places with a rich boy named Simon who looks just like him, but he discovers that Simon's half-siblings are planning to do him in to get his inheritance.
Tropes:
- A.I. Is a Crapshoot: Lenny's Vac-U-Bots have a convenient "Malevolent Sentience" setting. Bart triggers this on all of them, leading them to attack the partygoers.
- Air Quotes: Simon learns of Bart heading to Aspen. So he can share the news, Lisa takes him to Marge, telling her that "Bart" (air quotes included) has something to say. Marge comments that the air quotes already make her worried.
- Aesop Amnesia: Interestingly, Averted. Despite complaining that he wants a different family, Bart, who already learned the classic Lonely at the Top aesop back in "Burns' Heir," doesn't really want to ditch the rest of the Simpsons to live Simon's life at first. He agrees to pull the Prince and Pauper switch when he realizes it will get him out of being punished by Homer for ruining Lenny's party. His new lesson is to always ask what the other person is getting out of the deal.
- Analogy Backfire: Upon meeting Simon, Bart guesses that he's "happy as a clown" about being rich. Krusty immediately disproves this, walking out of a stall and saying "Oh yeah, I'm livin' the dream!", before coughing loudly and breathing with an oxygen mask.
- Arson, Murder, and Jaywalking: When Bart sees "his" new mansion, he is sequentially impressed by the size of it, the fancy-looking grand hall, and an awesome indoor pool. Next is an enormous library, which he's not interested in.
- As You Know: "And this is your home, sir. But of course, you already knew that."
- Be Careful What You Wish For: In the bathroom, Bart muses that he wants a different family. He gets his wish by switching places with Simon, where it turns out that his half-siblings are planning to kill him.
- Big Damn Heroes: Homer, in typically Homerish fashion ("This looks like a job for Captain Crazy!"), diving from a moving ski lift to save a careering Bart from a black diamond slope down which Simon's siblings have pushed him. It works, though not without incident.
- Bizarre Taste in Food: It's revealed that one of Bart's favorite foods is pasta made with Cheetos, covered in a sauce made of root beer. Simon is disgusted by it.
- Brick Joke: When Mr. Burns tells about his siblings and their early deaths, he mentions that most of them died from eating poisoned potatoes. In a later scene, Quenly offers her brother a potato.
- Brutal Honesty: Bart meets Devon and Quenly, then questions why they hate him. Quenly answers, "Because you're our half brother, you're blocking our full inheritance and we hate you."
- Cain and Abel: Mr. Burns warns "Simon" of danger from Devon and Quenly by relating the troubled history of how he inherited his fortune despite being the youngest of many potential heirs, causing Bart to realize that Simon only pulled the Prince and Pauper switch to protect himself from his half-siblings. Although they're working together, when they think they've succeeded, Quenly is quick to make Devon her next target.
- Digging Yourself Deeper: Lisa takes Simon aside and says that the real Bart isn't so passive and well-behaved, and would have thrown her out the window by now. Simon asks, "He would've defenestrated you?" Knowing that Bart wouldn't use such a big word, Lisa smugly comments, "You're just digging yourself even deeper."
- Distinction Without a Difference: Bart gets into a fight with Lisa in the car by flicking boogers at her. He justifies this by arguing that they're not boogers, but "clumps of rubber cement... which he stored in his nose." Lisa doesn't buy it.
- Eviler than Thou: After Devon and Quenly think they got rid of their half-brother, Quenly tries to make Devon eat a poisoned potato when he declares they'll split the inheritance.
- Foreshadowing:
- Lenny's party is held at the Woosterfield Hotel. Bart later meets Simon Woosterfield in the bathroom during the party.
- Mr. Burns warns Bart that his half-siblings may try to assassinate him during a ski trip. When Bart learns that he's going to Aspen with them, he remembers this and is horrified.
- Identical Stranger: Simon looks identical to Bart, but he has a fancier outfit and wears glasses. Played for Laughs shortly after Simon and Bart meet, when an older man who looks like Bart as an adult shows up. He lives in New York and is married to a woman... who looks like Milhouse. He offers to show Bart a picture of his children; Bart shudders in horror.
- Immediate Self-Contradiction: Homer says that he feels sorry for Simon, with the other Woosterfields being unloving and hostile. Once he sees Simon being served an ice cream sundae as he gets into his limo, Homer runs after it and begs to be taken away with them so he doesn't have to stay with his family.
- Jerkass Has a Point: Homer is right to be mad at Bart for playing one prank too many, as is everyone else. Especially since Homer missed out on a winning scratch-and-win because he had to stop Bart from causing more havoc.
- Karma Houdini: Devon and Quenly never receive any comeuppance for trying to get rid of their half-brother. Or at least Quenly, assuming if she succeeded in killing Devon with a poisoned potato.
- Loose Lips: When eating dinner at the Woosterfield mansion, Milhouse nearly exposes Bart (who was pretending to be Simon) by calling him by his real name in front of Simon's butler, however he dismisses it when Milhouse corrects himself calling Bart "Simon".
- Metaphorgotten: Upon realizing that his half-siblings are going to kill him, Bart quickly packs his suitcase, proclaiming that he has to "pack like he's never packed before". He realizes that he never has packed before. He then shoves a fish tank into his suitcase and is unable to close it.
- Ominous Latin Chanting: Parodied. A flashback shows what may have started Bart's bad behavior: Marge having one drop of alcohol land in her mouth while pregnant. The drop collides with the fetus, causing it to grow Bart's hair spikes. As this happens, an ominous chorus chants "ay caramba".
- One Drink Will Kill the Baby: Exaggerated; a single drop of beer landing in Marge's mouth while she was pregnant with Bart is apparently what turned him into such a hellion.
- Out-of-Character Alert: Simon, who is acting as Bart, lives with the Simpsons. He speaks in a much more dignified and refined manner, uses words that the real Bart wouldn't know, and pays attention to Grampa's rambling stories. The last of which is what leads Lisa to confront him. During the confrontation, Lisa hits Simon and he doesn't retaliate, erasing all remaining doubts Lisa still had about him not being Bart.
- Precocious Crush: Milhouse finds both Quenly and Devon attractive.Milhouse: Bart, I have a crush on your new sister.Bart: You had a crush on my old sister!Milhouse: Yeah, but that was never gonna happen.
- Prince and Pauper: To escape punishment from his family, Bart switches roles with Simon, a rich boy who claims to want a simpler life. Upon arriving at Simon's mansion, Bart realizes the true reason Simon switched places with him: to avoid his half-siblings, who are plotting to kill him to take their inheritance. Meanwhile, Simon stays with the Simpsons, where Lisa grows increasingly suspicious of him. Once Simon realizes the potential danger Bart is in, he confesses to the family and they go to rescue him.
- Purely Aesthetic Glasses: When Bart and Simon switch clothes, Bart also gets Simon's glasses, and somehow Simon is seeing perfectly fine without them, implying he doesn't really need them.
- The Resenter: Simon says his half-siblings Devon and Quenly resent him because their father left their mother to marry Simon's.
- Right in Front of Me: After Lenny's Vac-U-Bots turn evil, Chief Wiggum is doubtful that they'll find the culprit. He runs into Bart in the room with the gift bags, chanting "Kill! Kill! Kill!" and setting one of the bots loose. Wiggum is still confused and asks Bart who did it, not getting it until the bot vocalizes "Bart make bot bad."
- Spoiled Brat: Quenly is upset for being given a car that isn't the same one she wanted and rants that it was her worst Martin Luther King day ever.
- The Unfavorite: Throughout the first act, Bart bothers every member of the family (besides Maggie): he causes trouble at the Kwik-E-Mart and leads Homer to miss buying a winning lottery ticket, sprays cat pee on Marge's dress, and starts a fight with Lisa in the car. Homer and Marge call him out on his bad behavior, with Homer threatening to beat him, leading him to switch places with Simon to avoid punishment.
- We Want Our Jerk Back!: Lisa is bothered by Simon, as Bart, acting polite and denying his past bad behavior (which Simon wasn't aware of).Lisa: Okay, listen, you. I don't know who you are or what you've done with the real Bart. But... God help me, I want him back.
- Would Hit a Girl: When Lisa hit Simon, she told him Bart would have defenestrated her in retaliation.
- Wouldn't Hit a Girl: It came as a shock to Simon that Bart would have hurt his sister in retaliation of her hurting Bart.
- Would Hurt a Child: The mob at Lenny's party were fully on board to kill Bart over his prank with the Vac-U-Bots.
- You Are Grounded!: Marge tries to do it to Bart by first taking away his TV and video game privileges, which he points out she already did. She takes away his non-dice board game privileges as a result.
- Youngest Child Wins: Mr. Burns is his parents' youngest child and inherited their fortune because his siblings had premature deaths.
