Li'l Gideon, still fuming over his previous defeat, decides that the best revenge against the Pines Family is taking the Mystery Shack. However, Stan is too wily to be tricked, and too hard and cynical to be threatened by supernatural means.
Meanwhile, Dipper learns that Mabel has become (very slightly) taller than him, not helped by a slew of short jokes at his expense. Reading in Journal 3 about a place in the forest where animals change size, Dipper finds crystals that grow and shrink things depending on what side light is shone through, and makes a flashlight that can change his own height. Mabel finds out, and the twins fight for the flashlight- causing it to fall into Gideon's hands. Gideon shrinks the twins down and kidnaps them, but his attempt at ransom fails because Stan doesn't believe Gideon over the phone. Gideon decides that all he needs to do is shrink Stan himself, and take the Shack by force! While the twins escape and try to stop Gideon, Dipper learns why Mabel was so happy to be taller than him- She's felt that he's Always Someone Better, and that she wanted to have an edge for once.
At the Mystery Shack, Gideon confronts Stan in his less-than-stellar Mirror Room, but before he can use the flashlight, the twins use their shrinken size to get into Gideon's suit and tickle him, causing the villain to be incapacitated with laughter. Confused, Stan just pushes Gideon out of the Shack, causing him to drop the flashlight. The twins return to their normal sizes, meaning Mabel is still one-milimeter taller than Dipper, but now the brother is okay with it.
Back at the Gleeful house, Bud tries to console his son that he'll get revenge some other way. But Gideon wants more than revenge; he wants the Mystery Shack property because it holds a secret you couldn't possibly imagine...!
Tropes in this episode:
- Actually Pretty Funny: After his Jerkass Realization, Dipper manages to laugh at one of Mabel's short jokes.
- Always Someone Better: Mabel was giving Dipper a hard time about him being slightly shorter than her because he usually bests her at everything else and always seems to rub it in.
- Brain in a Jar: The Mystery Shack is shown to have two of these, both wearing a male and female wig.
- Breather Episode: This episode seems to be more light-hearted.
- Brick Joke: Mabel high-fives hard, which makes her Normal Hand Karate CHOP! more effective.
- Call-Back: The crystals were in the background in the first episode.
- Calling Your Attacks: "Normal Hand Karate CHOP!"
- Chekhov's Gun: Gideon's ticklishness.
- Color-Coded for Your Convenience: The height-altering crystals glow blue when enlarging something, and pink when shrinking something.
- Colossus Climb: Dipper, Mabel, and Soos do this to Gideon in order to get to the shrink ray.
- Comically Missing the Point: When Mabel thinks Dipper is hiding a wizard in the closet and she doesn't see a wizard in there.Mabel: An invisible wizard. Really, Dipper!
- Continuity Nod:
- Ducktective, first seen in "Headhunters", can be heard on the TV.
- Stan signs an insult on Gideon's contract like he previously did with Pacifica in "Irrational Treasure".
- Curb-Stomp Battle: Dipper vs. Mabel in chess, croquet and many other games. Dipper has dozens of victories and Mabel has none.
- Failed a Spot Check: Mabel demands to know how Dipper got taller so quickly, but doesn't seem to notice the massive chess pawn beside her.
- Giant Novelty Check: Offered at the beginning of the episode as part of Gideon's plot and again during the credits gag. Turns out the second one was for real.
- Hall of Mirrors: Grunkle Stan constructs a decidedly low budget one, in which the episode's climax takes place.
- Hypocritical Humor: A subtle one. when playing chess, Dipper corrects Mabel when she calls a pawn a 'little guy', then immediately refers to the knights as 'tiny horses'.
- I Have Your Wife: Gideon attempts this after he kidnaps Mabel and Dipper, but Stan doesn't believe him.
- I'll Never Tell You What I'm Telling You!: "You'll never find Stan... on the second door to the left, down the hall... Why did I say that?!"
- Incredible Shrinking Man: Gideon manages to take Dipper's flashlight and shrink both him and Mabel, with Soos being caught in the mess later. They spend the episode trying to grow back to their normal size.
- Island Help Message: Soos makes one of these out of mirror fragments.
- Jerkass Realization: Dipper realizes that he has been a jerk by always rubbing his victories in Mabel's face, which is what caused her to tease because of his size.
- Laughing Mad: Gideon at various points throughout the episode.
- Leaning on the Fourth Wall: Mabel remarks that "her favorite part [of a television show] is the theme song." This is followed immediately by the show's theme.
- Look Behind You: How Grunkle Stan thwarts Gideon's plan to unleash termites on the Mystery Shack.
- The Napoleon: It turns out Dipper doesn't like being teased on based on his height
- P.O.V. Cam: When Gideon shrinks the twins, we get a shot from their viewpoint at him as he becomes bigger in their vision.
- Saying Too Much: Both Mabel and Soos have trouble keeping information from Gideon.
- Shout-Out: In the scene where Dipper and Mabel play chess, the board is sitting on top of a skeleton which looks eerily similar to the "something that doesn't exist" from the Phineas and Ferb opening sequence.
- Shrink Ray: Dipper makes one by tying one of the crystals to a flashlight.
- Smart People Play Chess: Or at least, Dipper plays chess.
- Something We Forgot: Dipper and Mabel destroy the Growth/Shrink crystal after reverting back to their original sizes, but they forgot that Soos had been shrunk as well.Mabel: Glue.
Dipper: Lots of glue!
- Villain Opening Scene: The episode opens with Gideon in his room plotting on how to take the Mystery Shack.
- Wham Line: "[The Mystery Shack] holds a secret you can't possibly imagine!"
- A Wizard Did It: Mabel's best guess for Dipper suddenly growing.