Louis is disappointed that Evan doesn't appreciate Halloween. Eddie and the gang plot to crash an older girl's party. Jessica and Emery hear a strange voice coming from Grandma's room.
- Accidental Misnaming: Aside from thinking that handing out candy is a more age-appropriate activity for Evan, Louis wants him helping him at the door because he needs Evan to describe who people are dressed as; without him, he mistakes a child dressed as Willy Wonka for a pimp, and later, Evan (upset over being dragged out of the adult party) sabotages him into calling The Brain "Mouseboy".
- Acting Your Intellectual Age: Louis and Evan end up arguing because Louis has a love for Halloween that borders on Manchild levels, while Evan believes he's already outgrown the holiday and would rather mingle with adults than trick-or-treat.
- An Aesop: At the end of the Louis and Evan plot, Louis quotes the pumpkin's song from the start of the episode while stating that they should both be free to "do what they want to do, say what they want to say, live how they want to live, play how they want to play" without judging each other for enjoying age-inappropriate activities.
- Beware the Nice Ones: In The Tag, when Trent and Eddie are the last members of the friend group sitting outside the party as part of a dare, Trent gives a monologue on how Halloween is the only time he feels like he fits in and can let his dark side out. It's a lie, but it successfully scares Eddie away, and one of the older girls is impressed enough to invite Trent into the party.
- Coordinated Clothes: Louis is dressed as Jerry Seinfeld wearing "the puffy shirt", and wants Evan to join him as George Costanza, but trying to force Evan into the role leads to an argument. Emery willingly dresses as Kramer but wants to avoid handing out candy due to his ongoing year of bad luck, and Eddie just gives Louis a cold stare when asked to dress as Newman.
- Hates Small Talk: In addition to worrying about Evan outgrowing Halloween too fast, Louis doesn't want him attending the adult party because he hates the banal small talk that inevitably occurs at them; when he finds Evan's attending anyways and tries to drag him back, he ends up in a series of them.
- Innocently Insensitive: Near the start of the episode, when Eddie and his group of friends learn they're being excluded from a party just for being freshmen, Trent states that he finally knows what discrimination feels like; Eddie and Walter (the two non-Caucasians in the group) both give him a glare for saying that.
- Not So Above It All: Despite Evan considering Halloween's usual spookiness and hijinx beneath him, he admits that he wants Louis to escort him back to the adult party when it gets too dark, and they end up sharing some Seinfeld jokes during the walk.
- Shout-Out: In addition to all of the costumes throughout the episode, such as Louis trying to get his family to wear matching Seinfeld outfits and Evan wearing a Cocktail outfit to the adult party, the titular "plastic pumpkin" Evan buys in the opening scene (as an "efficient replacement" for the natural pumpkin Louis buys) plays the "Addams Groove" rap song from The Addams Family.
- Witch Hunt: Investigating what Grandma's up to leads to a group of people that Emery and Jessica mistake for a coven. It turns out the weird voice they had heard was just Grandma practicing English, and the "coven" is an English as Second Language class, because she knows the family uses English to hide secrets from her.
