The Flynn-Fletcher family goes on a vacation to Hawaii, where the boys bring Aqua Primates to life size while the manager attempts to bust them, Candace finds a pendant which she believes curses her with bad luck, and Phineas and Ferb even catch waves with surfer Laird Hamilton. Meanwhile, Doofenshmirtz plots to de-evolve Earth back to its primitive state with his De-Evolutionator, and he eventually gets stranded on an island.
Tropes:
- 555: Linda's phone number is 555-0142.
- Actor Allusion: Phill Lewis once again plays a bossy hotel manager on a Disney show trying to catch two boys causing mischief.
- Answer Cut: Major Monogram congratulates Perry on being able to subliminally persuade the family to travel to Hawaii so that he can find Doofenshmirtz there, and wonders how he did it. Cut to a flashback of Lawrence cleaning Perry's litter box, and noticing that his litter is shaped like the Hawaiian islands.
- Appease the Volcano God: Subverted. Candace finds a necklace she thinks is giving her bad luck, so Phineas and Ferb suggests climbing up a volcano and throwing it in. It turns out that the top of the "volcano" has a diner, and the necklaces are actually "your table is ready" alert devices, as well as coupons that you throw inside a miniature volcano installed in the diner for a random free menu item.
- Arson, Murder, and Jaywalking: Twice.
- The back of the "Aqua Primates" box showcase the creatures crowning their queen, fighting robots, and designing websites.
- When asked if the brothers can dump their evolved Aqua Primates into the pool, the lifeguard reads off the pool rules: no running, diving, pushing or modern expressionism.
- As Himself: Surfing sensation Laird Hamilton appears in the second part.
- Bad Luck Charm: Candace finds a tiki charm which appears to give her bad luck, and keeps coming back when she tries to get rid of it. She interprets a local's advice to be "throw it into the volcano", but it turns out that there is a restaurant on top of the mountain, and the charm is a "your table is ready" alert device. After having bad luck throughout the episode, she refuses her free dessert simply because it was something the charm brought her. She then continues to suffer bad luck without it, just like usual.
- Bamboo Technology: Doof uses a bamboo metal detector on the island. He also "creates" the Sand-inator, which he claims will cause sand to go into people's pants.
- Bland-Name Product: The tub of brine shrimp that Phineas and Ferb get is called "Aqua Primates" or "A-Primes" for short, since the "Sea-Monkeys" name is a registered trademark.
- Borrowed Catchphrase:
- The hotel manager asks for a bellhop to take the Flynn-Fletcher's bag and pet platypus, but then notices the pet cage is empty.
Hotel Manager: Hey, where's Perry?- Later, Phineas lampshades when he says, "Not to be redundant, but where's Perry?"
- In part 2, when Phineas tells Candace he and Ferb are going to try some semiaquatic activities after doing all the land stuff, Candace replies, "Speaking of semiaquatic, where's Perry?"
- Also in part 2, when a man is about to propose to his girlfriend, he innocently asks for a sign if it wasn't meant to be. When Candace slams into the window, he yells, "This single guy is out, PEACE!"
- Brick Joke: In Part 1, while surfing, Lawrence lists off a slew of surfing slang terms, prompting Linda to say "You got all that off the Internet, didn't you?". Later, while Phineas and Ferb are surfing in Part 2, Ferb also uses surfer slang, prompting Phineas to say the same thing.
- Cargo Cult: Doofenshmirtz planned to dismantle the De-Evolutionator entirely since he's through with the machine, but decided not to after seeing his crab minions worship it.
- Chekhov's Gag: When Phineas and Ferb first put the A-Primes in water, he discovers that they only have one trick - moving towards a light source. At the end of Part 1, as the (now giant-sized) A-Primes are running around the hotel chaotically, Phineas and Ferb manage to round them up by using a giant flashlight.
- Continuity Nod: Doofenshmirtz mispronounces "boat" as "BO-AT" like he does in "Interview with a Platypus", but mentions that he has since been told how to pronounce it correctly.
- Devolution Device: The De-Evolutionator can de-evolve and evolve anyone struck by it. Doofenshmirtz plans to use it to de-evolve the entire Tri-State Area until his plans got thwarted by Perry, and a stray shot from the inator fires into Phineas and Ferb's troop of Aqua Primates, turning them into regular humans before Linda and Lawrence finds out.
- Formula-Breaking Episode: Despite this being a 22-minute episode, this is the only two-parter in which the two parts have different storylines, although some parts of the Doof-Perry plotline from the first part carry over into the second part.
- Fully-Clothed Nudity: When Doofenshmirtz uses the De-Evolutionator to turn himself from single-cell organism back to human, he evolves already wearing underpants and socks. He even lampshades it:Doofenshmirtz: It's strange that my underwear and socks evolved with me.
- Gratuitous Spanish: Lawrence attempts to try speaking Hawaiian to the manager of the hotel they're staying at, but he mistakenly speaks Spanish instead. The hotel manager is quick to point out that they speak English since, after all, Hawaii is in the United States.
- I Fell for Hours: Candace falls down a giant waterfall for an entire 10 seconds of the episode, screaming all the way down.
- Inevitable Waterfall: When Candace gets stuck in a hot tub on the back of a truck, the tub accidentally falls into a river. Things seem okay... until she spots a waterfall.
- Innocently Insensitive: The hotel manager points Lawrence and Linda towards the human-sized Aqua Primates that wreaked havoc on the hotel, calling them "slimy, disgusting creatures", just after the De-Evolutionator ray hits the A-Prime herd and evolves them into humans. Linda calls the manager out, thinking he's being rude to his guests.
- My Brain Is Big: In Part 2, Doofenshmirtz uses the De-Evolutionator to increase the size of his brain; his cranium swells up to such a large size that he loses his balance and is unable to stand up.Doofenshmirtz: You know, now that I'm so smart, I don't think that was such a good idea.
- No Fourth Wall: When Candace receives the totem, a harp glissando plays.Candace: A good luck charm... with its own theme music!
- Pass the Popcorn: Candace is eating some luau food when she sees the manager's busting attempt has failed.
- Property Line: After the two are stranded in the island, Doofenshmirtz draws a line in the sand, exclaiming that Perry is forbidden from crossing over to his side. Immediately after, a coconut falls into Perry's side, which Doofenshmirtz wants, but Perry doesn't give because of the line. He erases part of the line in desperation, saying that it's not an actual barrier.
- Punny Name: Part 2 takes place in the fictional island of "Wa Ta Lot Ta Hoie".note
- Resized Vocals: Doofenshmirtz as a single-cell organism has a higher-pitched voice.
- Rhetorical Question Blunder: In the beginning of Part 2, Doofenshmirtz (as a single-cell organism) asks other organisms around him "Who could have guessed that my De-Evolutionator would backfire on me?" Immediately, all the other organisms raise their pseudopods (which look like hands), prompting Doofenshmirtz to say "Alright, put your pseudopods down!".
- Scooby-Dooby Doors: Happens in one of the hotel's hallways as Phineas and Ferb try to chase after the A-Primes (and the hotel manager tries to chase after both of them). At one point, the Giant Floating Baby Head makes an appearance.
- Screw This, I'm Outta Here: Even after finding out the totem was just an indicator of when her table at the restaurant would be ready, Candace wants nothing more to do with it, saying, "Candace is out, PEACE!"
- Sea Aping: This episode features the titular step-brothers using growth elixir to turn the "A-Primes" (short for Aqua-Primates) human-sized. Like the Sea-Monkeys, the A-Primes are depicted as having a whole civilization.Phineas: Check this out. "Aqua Primates". A-Primes, Ferb. The back of the box shows them crowning the queen, fighting robots, and designing websites. Ferb, we've totally got to get this!
- Shapeshifter Showdown: As Doofenshmirtz and Perry fight in Part 1, the De-Evolutionator fires randomly at both of them, causing them to transform into different animals while they fight.
- Shout-Out:
- Candace's plotline in the second part is lifted straight out of The Brady Bunch's Hawaiian episode.
- In Part 2, the De-evolution-inator becomes a shrine for crabs on the island. Doof even acknowledges how "Kubrick-y" they are acting around it.
- Skewed Priorities: When Doof becomes an amoeba, his first concern is how he's going to drive home.
- Special Guest: Phill Lewis as the manager who takes over for Candace, and professional surfer Laird Hamilton.
- Superstition Episode: The second part revolves around Candace finding a tiki necklace that she believes has given her bad luck.
- Swallowed Whole: Doofenshmirtz ends Part 2 stuck inside the belly of a whale. note
- Tempting Fate: A guy proposing to his girlfriend says, "If this wasn't meant to be, someone give me a sign!" Cue Candace crashing into the window right beside them.Guy: Well that's good enough for me. This single guy is out, peace!
- Vacation Episode: The Flynn-Fletchers go on a vacation to Hawaii, thanks to Perry secretly persuading them.
- Welcome to My World: When the aghast manager sits next to Candace on the pool chair after failing to bust the boys, Candace just smiles and says, "Oh, dude. I know, right?"
