Phineas and Ferb build a shrinking submarine so they can retrieve Isabella's sash (which was eaten by her chihuahua, Pinky). Unfortunately, they end up inside Candace by mistake.
Meanwhile, Dr. Doofenshmirtz builds a device that will destroy people who can't make up their mind.
Tropes
- Anuscape Plan: During the song "Hemoglobin Highway", one of the lyrics say "Slow down before we reach the colon", implying that the brothers do not wanna go there.
- Aw, Look! They Really Do Love Each Other: Perry's concern that Phineas and Ferb could be targeted by Doofenshmirtz's invention is the first sign that he sees them as more than just a cover identity.
- Be Careful What You Wish For: Doofenshmirtz, in an attempt to add some variety to his and Perry's routine, shifts around the steps of their daily plot, specifically this time telling Perry his scheme first. When Perry learns just how destructive his current scheme is note , Perry immediately immobilizes him, which Doof lampshades.
- Breaking Old Trends: In-Universe. Doofenshmirtz tells Perry his scheme first rather than trap him.
- Crazy-Prepared: Doofenshmirtz did actually prepare a back-up trap for Perry should he be immobilized early on and had a hairpin ready to pick handcuff locks. A hidden flat-surface magnet belt sticks Perry to the wall when he opens a bag, allowing Doof to free himself. He states he had another belt in another bag as a precaution, but this proves to be his undoing.
- Early-Installment Weirdness: This is the only episode where Doofenshmirtz attempts to perform such a legitimately evil action as mass murder simply because of indecisiveness rather than his usual Poke the Poodle-type schemes. Anytime another villain shows up later on that tries something like this, Doof is always shown to be against them.
- "Fantastic Voyage" Plot: The whole episode involves Phineas and Ferb originally shrinking themselves to enter Pinky's body, but end up in Candace's body by accident.
- Here We Go Again!: Subverted. It looks like Candace is going to eat the re-miniaturized submarine again with Doofenshmirtz inside this time, but then Pinky eats the sandwich instead.
- Idiot Ball:
- Yeah, Candace, let's eat the mysterious cheese sandwich on the plate on the floor of the empty garage. That's a great idea! (Plus, aren't you supposed to be lactose intolerant?)
- Doofenshmirtz was smart enough to prepare a back-up trap for Perry in two separate bags. After Perry is immobilized by one, Doof pats himself on the back, but he's dumb enough to open the second bag just to prove how far he thought this ahead. It takes him a moment for him to realize how badly he screwed up.
- Irony: Doofenshmirtz says he's wondering if the Make-Up-Your-Mind-inator has the right name. He admits that being unable to make up his mind on this is rather funny.
- Lampshade Hanging: Doofenshmirtz and later Monogram describe the usual routine in Perry plots.Doofenshmirtz: Perry the Platypus! I—y'know, we always do the same thing. I have a scheme, you try to stop me, I trap you, I tell you my scheme, you escape, then we fight, and I'm defeated. Let's mix it up a little.
- Non-Indicative Name: The Make-Up-Your-Mind-Inator's name implies that it would force people to make decisions quickly. It's actually a sort of Death Ray that Doofenshmirtz plans to use to destroy anyone who can't make up their mind.
- O.O.C. Is Serious Business: When Perry is told by Doofenshmirtz what his Make-Up-Your-Mind-inator does (kill all who cannot make up their mind (which includes Phineas and Ferb)), Perry immediately takes Doof down, rather than doing the pair's normal routine.
- Reactive Continuous Scream: The rare joyous variation occurs in the beginning of the episode, where Candace, Stacy, and Jenny exchange excited shrieks on-phone due to Candace's soon-to-be-date with Jeremy. Their constant shrieking annoys Phineas and Ferb, so they decide to figure out what they want to invent outside instead.
- Shrink Ray: One of the things Phineas and Ferb had to choose between to build during the episode. In the end, it was combined into one idea with the submarine.
- Squick: In-universe. When Phineas finds out that they were inside Candace and during her date with Jeremy (meaning they were also on a date with Jeremy), Ferb said both times that it was creepy on so many levels.
- The Stinger: In the sub inside Pinky, Doofenshmirtz realizes he's in a dog and vows to pee wherever he wants in the Tri-State Area. An Evil Laugh is then interrupted by a depressed Doof asking, "Oh, what am I doing with my life?"
- This Is Wrong on So Many Levels!: See above.
- What Happened to the Mouse?: It's not clear what happened to the Make-Up-Your-Mind-Inator after Doofenshmirtz was trapped inside the submarine.
