The crossover special with Phineas and Ferb. Continuing where Fungus Among Us left off, Milo, Dakota, Cavendish and Orton Mahlson try to convince Dr. Heinz Doofenshmirtz to build a time machine and stop Derek's plans in 1965. Coincidentally, Doofenshmirtz already made a Time Traveler-Inator in order to go to 1965 to get some Wyatt Burp orange soda, which was discontinued in the 70s due to being harmful to the environment. However, Doof still needs time juice in order to make it work, which hasn't been discovered yet. Fortunately, the clock from the time stream Milo was given earlier contains a bit of time juice, so Milo and Diogee go back home with Perry the Platypus to pick it up. After doing so, the Time Traveler-Inator is set, but the Pistachions have discovered Doof's home, so Milo decides to distract them so Dakota, Cavendish, Orton, Doof and Perry can travel back in time.
Meanwhile, Zack and Melissa manage to escape their prison along with Buford and Baljeet, who had discovered a project called M.U.L.C.H. is being worked on, although they do not know its purpose. The four accidentally run into Derek, who had assumed the role of Orton for years without taking his mask off, and thus got his actual head shaped after Dr. Zone. Derek explains his plan to continue his father's quest for world domination, which took longer to accomplish than expected due to him being terrible at running the Dr. Zone TV show… only to discover Zack, Melissa, Buford and Baljeet already ran off while he was monologuing. The four get cornered alongside Candace, and are eventually saved by Phineas and Ferb. The group then meets up with Milo and Diogee.
Milo, Melissa, Zack, Phineas, Ferb, Candace, Buford and Baljeet then go to Phineas and Ferb's hideout and try to find a way to fend off the Pistachions without Murphy's Law getting in the way, while Cavendish, Dakota, Orton, Perry and Doof try to avert the takeover in the past, but then get stuck on an island in the present. Will they succeed before Derek can unleash his M.U.L.C.H. project?
- Advertised Extra: Isabella doesn’t have much of a role in the special, having only two lines throughout the show, both of which involve her just saying her Catchphrase.
- Major Monogram too, he's basically a cameo. He would have a somewhat bigger role in future episodes.
- Big Damn Heroes:
- Phineas & Ferb saving Melissa, Zack, Buford, Baljeet & Candace in their tennis-playing robots.
- Doof, Dakota, Cavendish, Orton and the paradox Dakotas making the save before the M.U.L.C.H. is ready.
- Isabella and the Fireside Girls delivering the Murphy Suit.
- Born Lucky: The titular "Phineas and Ferb Effect" is actually the source of all of the beneficial coincidences of their show - It's the opposite of Murphy's Law. Just as Milo's presence makes things go wrong, Phineas or Ferb's presence makes things go right.note Baljeet even figures out how to use this to weaponize Murphy's Law.
- Brick Joke: After Milo calls the Pistachions "nut-jobbers", one of them retorts "well, it describes us, but it's still rude". Phineas later says the same thing after a Pistachion calls him a "meatbag".
- Broken Pedestal: Cavendish slowly loses his respect for Doof after seeing how eccentric and inept he can be. It gets repaired when Doof shows what he can do if properly motivated.
- The Cameo:
- Major Monogram's appearance.
- King Pistachion appears in a flashback as Derek recalls the advice he gave his children.
- The Cavalry: As things look bleak for Milo, Phineas and Ferb, who are captured by the Pistachions and are about to get M.U.L.C.H.'ed, Doofenshmirtz, Perry, Dakota, Cavendish, Orton and all the lost Dakota paradoxes fly in, armed with Wyatt Burp soda. Isabella and the Fireside Girls also show up to free Phineas, Ferb and Milo and bring them the Murphy's Law Suit.
- Call-Back:
- Doof's Time Travel technology uses elements from Xavier Onassis' Time Machine.
- Lots to "Missing Milo" such as the clock Dakota gave Milo.
- In "Missing Milo" after hearing the creator of time travel was named "Professor Time", Milo suggested he probably changed his name for branding purposes. In this episode, when Doof points out his name isn't Professor Time, Dakota tells him he changed it for branding purposes.
- Milo offers Phineas and Ferb a blowtorch and some peanut butter to help fix the Murphy's Law Suit.
- Chekhov's Gun: The Wyatt Burp orange soda. Introduced as a discontinued soda drink because it harmed the environment, it's used against the Pistachions in the Final Battle.Doofenshmirtz: (To the Pistachions) So here's what I've figured out: I'm not the environment, but you are!
- The Complainer Is Always Wrong: Candace is initially hesitant to involve Milo in the kids' plan to fight the Pistachions out of the belief that Murphy's Law makes him too big of a liability. She changes her mind after witnessing it save her multiple times, believing that it can instead somehow be weaponized.
- Continuity Nod: Way too many to list.
- Darkest Hour: Many of the supporting cast of both shows have been converted into Pistachions and our heroes seemingly have no way to save them or themselves. Then the events under Retroactive Preparation (see below) happen.
- Don't Explain the Joke: Buford keeps over-explaining Phineas's one-liners, and Baljeet responds "We get it, Buford!" both times.
- Dramatic Gun Cock: Parodied with Diogee, who cocks his leg in this fashion.
- Either "World Domination", or Something About Bananas: When Perry volunteers to go with Milo to get the time-juice clock from his house, Doof interprets his chattering this way:Doofenshmirtz: He's either saying he's going with you, or he regrets the impulsive mistakes of his youth. I'm not sure.
- Faceship: The Murphy's Law Suit that Phineas and Ferb build is modeled after the likeness of Milo.
- Fan Boy: Cavendish is a big fan of Professor Time: his outfit is a green version of Time's outfit and he wears Professor Time-themed underpants, which he almost wanted to show to Doofenshmirtz. Cavendish even Squees when Future Doof, now assuming the Professor Time name, shows up.
- Baljeet happens to be a fan of the Lumberzacks, carrying their well-known single with him. When Buford in turn mentions the Pistachion guards were singing the tune as well, it gives Melissa an idea.
- Fire-Forged Friends: From the moment they meet, Phineas and Ferb immediately take a liking to Milo, even recognizing that he's related to Murphy's Law. Over the course of the episode, they learn to work together against the pistachio army and by the end of the episode, it's clear that their adventures have clearly bonded them together, and Milo and company invites Phineas and Ferb and their friends to stop by his part of town anytime.
- Forced Transformation: The purpose of M.U.L.C.H. is to convert humans to Pistachions, as revealed in its acronym: Machine Used for Literally Converting Humans… To Plants. Derek actually succeeded in getting some of Phineas, Ferb and Milo's friends, and the Giant Floating Baby Head, converted and turned to his side. They are of course turned back to normal when Orton and Professor Time managed to slay Derek in 1955... except for Bradley, whose right arm is still a branchy tendril.
- Foreshadowing:
- While at the Island of the Lost Dakotas, Doof accidentally spills Wyatt Burp orange soda on a plant and it dies.
- Also lampshaded in the episode itself:
Pistachion #1: Hey, it's Zack of the Lumberzacks. We should get his autograph before, well, you know.Pistachion #2: Stop foreshadowing, Bob. - For Want Of A Nail: Due to Derek impersonating Orson, but not being good at running a TV show, Dr. Zone was cancelled after two episodes and never achieved the level of popularity it normally has In-Universe. This is also why Time Ape isn't on Sara's shirt, unlike usual.
- Freeze-Frame Bonus:
- While changing channels on his monitor, Doof flashes by an episode of Horse in a Bookcase, along with several shows from the Phineas and Ferb episode "Ferb TV".
- If you look close at Orton's memoirs when Professor Time displays them, you can see the note he wrote in "Fungus Among Us" with "aaaah!" and a screaming face, on the front.
- Fun with Acronyms: M.U.L.C.H. stands for Machine Used for Literally Converting Humans… To Plants. Derek insists the last two letters are silent.
- Go Through Me: Cavendish tries this to protect Dakota from the Pistachions after finding out about the Island of Lost Dakotas.
- Heel–Face Turn: As mentioned in My God, What Have I Done? below, the giant Pistachion undergoes one of these.
- Hypocritical Humor: After hearing Cavendish's impression of him, Doof asks if that is really what he sounds like, Dakota replies, "Yes, your voice is really annoying." It should be noted that both Dakota and Doof are voiced by Dan Povenmire.
- Internal Reveal: Cavendish learns about the Island of Lost Dakotas.
- Leaning on the Fourth Wall:
- After making the save in their tennis playing robot, Ferb comments that "it's been a long time" since he talked. Phineas replies, "yes, yes it has" before looking right at the audience.
- At the end, Milo invites the P&F gang to "Crossover any time"…since they live on the other side of the city.
- Mistaken for Aliens: Zack and Melissa think that Candace could be a pistachion, mainly because of her doubt in Milo, and also because of her long neck.
- Mobile Kiosk: Doof's first Time Travel-Inator is shaped after a taco stand… with the stand itself shaped after a taco.
- My God, What Have I Done?: During the final act, Derek sends in the giant Pistachion from "Fungus Among Us" to attack Zack, Melissa, Orton, Dakota and Cavendish. However, upon viewing all the carnage and tragedy on the battlefield, the giant Pistachion realizes he's doing more harm than good, and decides to leave.
- Near-Villain Victory: The Pistachions had converted most of the main characters and would've defeated the others had Professor Time not shown up. Derek actually notes this before he fades out of existence.Derek: No! It can't be! It was working! We had won! How could it all go so wrong?!
Milo: Well, that's Murphy's Law for ya! - Nothing Is the Same Anymore: For MML anyway. The destruction of DEI leads to Doof moving in with the Murphys and becoming a recurring character for the season, also leading to cameos from other P&F characters. Also, Bradley's right arm remains part plant.
- Plant Mooks: What everyone except for Phineas, Ferb, Milo, Doofenshmirtz, and Orten are turned into.
- Previously on…: Like "Fungus Among Us", "The Phineas and Ferb Effect" has this as a Cold Open. This time, it's combined with Let Me Get This Straight..., as Doofenshmirtz recaps the events that were likely being told to him before, and asks them that what Milo and co. were saying is… that they're NOT the pizza delivery guy.
- Pre-Mortem One-Liner: Orton, now having fully embraced being Dr. Zone, confronts Derek in 1955 with Professor Time's help:Orton: You're the Pistachion that started all of this! "Time" is not on your side!
Professor Time: Yeah! Have some orange soda! On the house! (the two proceed to spray Derek with orange soda, killing him) - Retroactive Preparation: As things look dire for our heroes, Doof gives a Rousing Speech, with Orton remarking that it'll be great for his memoirs. This gives Present Doofenshmirtz an idea, and Future Doofenshmirtz suddenly shows up, now assuming the name Professor Time, explaining how he remembered that he should go back because he read Orton's memoirs. He then invites Orton to go back to 1955 and defeat Derek before he could start his evil plan. They also take along the letter from Milo to deliver to a week in the past.
- Ridiculously Successful Future Self: Professor Time is more respected and successful than Doof's ever been.
- Running Gag: People assuming Melissa & Zack are a couple, Doof comparing various situations to being like a sitcom.
- Saved by Canon: Since this is set before "Act Your Age", the Phineas & Ferb characters will be fine. And not remain as Pistachions.
- Subverted with Doofenshmirtz Evil Inc. Despite being fine in "Act Your Age", the building got leveled completely at the very end, and Doof ends up crashing at Milo's house. Although it is likely the building will get rebuilt.
- She's Not My Girlfriend: Buford and Baljeet make constant remarks about Zack and Melissa being a couple, which they deny.
- Social Media Before Reason: The Pistachions eventually manage to track down the kids at their secret base and capture them thanks to Buford deciding to livestream their group building weapons.
- Stealth Pun: While Milo is fighting some Pistachions in a staircase at Doofenshmirtz Evil Inc., the Waltz of the Sugar Plum Fairy from Tchaikovsky's Nutcracker suite plays in the background.
- Strange Minds Think Alike: Doof wants the Wyatt Burp orange soda in spite of knowing it's harmful to the environment because, as he says, he's "not the environment". When the Lost Dakotas are revealed as makers of that soda, one of them says the same thing.
- Toxic, Inc.: The Wyatt Burp company got closed down in the 70s because its orange soda was harmful to the environment. This doesn't include humans, but it DOES include Pistachions.
- Transhuman Treachery: All of the family/friends of the main characters easily turn on them and attempt to attack them after being converted into Pistachions.
- Winds of Destiny, Change!: Phineas and Ferb manage to weaponize Murphy's Law with the aptly named Murphy's Law Suit, naturally manned by them and Milo as the power sources.
