When the kids decide to play hide and seek on a rainy day, Phineas and Ferb invent a machine that shrinks them so they can hide better, but problems arise when Candace gets her hands on it.
Meanwhile, Doofenshmirtz attaches a nanobot to Perry so he can see where he lives, and he witnesses the kids while doing so.
First appearance of Irving DuBois, Phineas and Ferb's self-proclaimed biggest fan.
Tropes:
- Big "WHAT?!": By Candace when she realizes the big idea disappeared, leaving Mom and Vivian to assume she's gone nuts.
- Broken Pedestal: Irving is disappointed when he finds out Phineas and Ferb don't have a plan and have been ad libbing this entire time.Irving: How heroes fall.
- Call-Back: While planning the big idea, Phineas mentions the shrinking technology from their submarine adventure.
- Carcass Sleeping Bag: When Baljeet gets stuck on the light fixture next to two dead flies, the air conditioner is freezing him. A few scenes later, when the kids fly up in the nanobot to rescue him, they see something moving in one of the dead flies. It turns out that Baljeet had to lie down in one of the fly carcasses to keep warm.Baljeet: I did what I had to do to survive!
- Continuity Nod:
- Irving's book contains pictures of past moments, like the rollercoaster, the chariot race, and when they had "that soup".
- A more subtle nod occurs during the song, "When You're Small": the movie the kids are watching on the television is the same movie that inspired Phineas and Ferb to build the transporters in "Does this Duckbill Make Me Look Fat?".
- Phiness mentions using the shrinking technology from his and Ferb's submarine adventure, which has happened in "Journey to the Center of Candace".
- Borrowed Catchphrase: Irving asks Phineas if he can say "Where's Perry?"; although confused, Phineas lets him say it, but Irving keeps butchering the line and coming up with different variations of it.
- Description Cut: When Doofenshmirtz sees the kids with the nanobot, he hits several random buttons out of frustration and loses the video feed entirely. He then says, "I hope it doesn't go rogue". The scene then cuts to the kids fleeing in terror from the nanobot as it goes rogue.
- Ding-Dong-Ditch Distraction: Discussed. Doofenshmirtz plans to do this to Perry's house after he discovers his address.
- Epic Fail: Irving attempts to tie the last thread around the bug, but bumps into a table leg, so Isabella does it for him.
- Good-Times Montage: When the kids are enjoying the perks of being small.
- Green Aesop: Parodied. Doof's evil plan involves throwing a glass bottle into a trash can. But it turns out to be a ruse for Doof to put a tracking device onto Perry.
- Hair Memento: Phineas gets a little uncomfortable when he sees Irving has a lock of Ferb's hair in his scrapbook.Irving: Don't touch it!
- Hypocritical Humor: When Irving shows the kids his scrapbook, Baljeet says "What a nerd". Baljeet. The same guy who is an overachieving nerd.
- I'm Okay!: Baljeet says this after he gets stuck on the light fixture in the entrance of the Flynn-Fletcher house.
- Happens again after Irving accidentally runs into a table leg.
- I'm Your Biggest Fan: Said verbatim by Irving when he introduces himself to Phineas and Ferb.
- Incredible Shrinking Man: What the big idea is for the episode.
- Left the Background Music On: At the end of "When You're Small", the music is revealed to have been played by a band made up of amoebae.
- Literal Surveillance Bug: Doofenshmirtz secretly attaches a tracker to Perry's back, which he then activates into a bug-shaped robot once Perry's home. He plans to use this robot to find out where Perry lives.
- Overly Long Gag: Doof's rambling voicemail to Major Monogram.
- Percussive Maintenance: After the nanobot gets damaged the first time, Doofenshmirtz pounds on the screen of the video receiver in his lab. Surprisingly, it reactivates the camera.Doofenshmirtz: Oh, hey, random pounding works!
- Rain, Rain, Go Away: The plot kicks off when the gang has to stay indoors because of the rain. This is also one of the first times to depict rain in Danville.Buford: What kinda fun can we have when it's rainin'?
Isabella: We could talk about our feelings?
(Beat)
Buford: Okay, I'll rephrase it. "What kinda fun can we have when it's rainin'?"
Baljeet: I would not mind talking about my feelings.
(Buford punches Baljeet.)
Buford: How do you feel now?
Baljeet: In pain.
Buford: There. We're done. - The Sixth Ranger: Irving is first introduced in this episode. However, he was originally going to appear from the beginning, but when Disney asked for more diversity, Baljeet was created instead.
- Squee: Irving squeals with delight when Phineas says "Ferb, I know what we're gonna do today".
- This Is the Part Where...: Apparently, Irving is aware of Candace's attempts to bust her brothers, as he fangirls at this moment, baffling Phineas.
- Victorious Roar: Buford lets out one, complete with Primal Chest-Pound, after defeating Doof's nanobot.
- Victory Is Boring: Doofenshmirtz attempts to use the Self-Destruct Mechanism he installed in his robot as a last ditch attempt to take Perry down. It doesn't work (the robot's body is over at Mrs. Garcia-Shapiro's house, which destroys itself along with Phineas and Ferb's shrinking device), but Doofenshmirtz thinks he succeeds anyway, and then he immediately laments how empty he feels afterward.Doofenshmirtz: Well, that's done! And no comeuppance! (Beat) Why do I feel so empty?
- Visual Pun: A shrunken Baljeet asks anyone to take a picture of him next to a dust bunny, a clod of dust shaped like a rabbit.
