Averted by Dr. Doofenshmirtz himself, who, while a Bumbling Dad at times, visits none of the horrors of his childhood on his own daughter, and tries as much as he can to prove to her that he really cares for her.
"Picture This" introduces Baljeet's uncle Maulik, named after Baljeet's voice actor Maulik Pancholy.
In "Phineas And Ferb Musical Cliptastic Countdown" the show was hosted by Major Monogram and Dr. Doofenshmirtz, who are both voiced by the creators.
In "Nerds of A Feather", Doof pitches a show to a man named Jeff MacGarland.
Which makes it even more funny to anyone who knows the creators well enough to get the "I got my own show!!" jokes. For those who don't, Doofenshmirtz's voice actor (the show's executive producer) used to work with MacFarlane on Family Guy.
In "Ladies and Gentlemen: Meet Max Modem!", Linda mentions that she only lip-synced "I'm Lindana and I Wanna Have Fun". The person who actually sings that song isn't the same person who voices Linda. (it's Olivia Olson, who voices Vanessa)
Richard O'Brien, who does the voice of the boys' dad, is best known for his role in Rocky Horror Picture Show and is very confused when the horror film he's watching has no rock and roll musical numbers.
Adorkable: The titular characters themselves, their dad, Baljeet, Carl, and even Doofenshmirtz on more than one occasion! There's practically no shortage of cute nerdiness in this show.
Adult Fear: In "Phineas and Ferb Get Busted", Candace experiences this when she discovers that her brothers got sent to a Military School where they and many other children are being taught that imagination is wrong and tortured into slack-jawed obedience. Thank God that was All Just a Dream.
In "Wizard of Odd": Enjoy every minute of your summer, because summer won't last forever. Happiness is in the journey not in the goal.
"Phineas and Ferb Get Busted" and "Phineas and Ferb's Quantum Boogaloo" are also very pro-imagination and creativity.
Affably Evil: Dr. Doof. Taken Up to Eleven in "Skiddly Whiffers": His whole scheme isn't really an evil scheme at all, but a plan to overprotect his daughter while she's camping in the woods. He even apologizes to Perry for not having a scheme and begs him for help in this effort.
This is only one example, it isn't the first or the last time Perry has helped Doof.
Affectionate Gesture to the Head: Done by Candace to Ferb in the final song sequence in "Summer Belongs to You". And considering it's pretty much the only time so far that she's shown physical affection to her little stepbrother, it's nothing short of adorable.
Affectionate Nickname: Inverted with Jeremy. In the episode "The Baljeatles", where Jeremy suddenly becomes The Nicknamer and nicknames everybody except Candace. When she finally stops trying to make him nickname her and confronts him about it, he says "I call you Candace, but not because I don't care enough to come up with a cute nickname for you. I call you Candace 'cause I happen to really like that name." Aww...
Affectionate Parody: The entire Agent P. and Dr. D plots are a parody of James Bond and spy-films in general, but the entire episode "Elementary, My Dear Stacy" becomes one when Perry is forced to work with British human Double-O-O.
Ageless Birthday Episode: The episode "Phineas' Birthday Clip-O-Rama" centers around Phineas' birthday, but his age remains a mystery (all we know is that despite aging a year he is still "younger than 15").
Aliens Steal Cattle: A blink-and-you'll-miss-it gag in "No More Bunny Business" - when Phineas is trying out his x-ray specs, he looks into one funny-looking house to see aliens experimenting on a cow.
A.I. Is a Crapshoot: Doof's more advanced robotic replacement for Norm, which immediately turns on him when supercharged with a wave of energy. Averted by Norm himself, who remains loyal to Doofenshmirtz and defeats the much larger and more advanced robot. With a cup of coffee.
There's also the Phinedroids and Ferbots from "I, Brobot". After completing all the projects the brothers set out for them, the robots begin designing their own, then build their own overpriced coffee shop (Phineas: "That is so 90's!"), then turn on their creators when Phineas tries to shut them down.
Programming an artificial intelligence into a giant tower laden with traps might not have been one of the boys' best moves. Admittedly, its repeated attempts to kill them and trap the entire galaxy might have just been because of Doof's "rudeinator".
Inverted with Robot Candace in "Where's Perry? (Part 2)".
All Animals Are Dogs: Perry exhibits various dog traits, like twitching his leg when he's being petted, turning in circles before lying down, and moving his legs as if running in his sleep. Justified in that he's pretending to be a mindless domesticated animal as a cover for his real job.
Part of the reason a platypus was chosen as Perry's species was because they could make him act in just about any manner and very few people would notice if it was inaccurate - since, y'know, most people don't really think too much about how a platypus would really act.
Alliterative Name: Let's see. There's Perry the Platypus (along with Peter the Panda, Sergei the Snail, and presumably the rest of the agency), Doctor Doofenshmirtz, Major Monogram, Inspector Initials, Jeremy Johnson (who gets double points for being voiced by Mitchel Musso), Ferb Fletcher, Professor Poofenplotz ... also Phineas Flynn and Carl Karl, phonetically.
In "Does This Duckbill Make Me Look Fat?", Doofenshmirtz tries to take advantage of this stereotype when fighting Perry who is in Candace's body. He tries to distract him (her?) by saying "Look, a shoe sale!" before running away. Oddly enough, it works.
Dr. Doof: You were wearing headphones? So you didn't hear a thing I said? Vanessa: Why do you think I wear the headphones?
Also when Candace meets Tiny Cowboy in the "Meat Loaf" episode, and Linda asks why they're large and not cowboys.
Linda does one embarrassing thing after another for Candace in "Does This Duckbill Make Me Look Fat?"
Amazing Technicolor Wildlife: All platypuses (not platypi, maybe platypodes?) are colored a bright turquoise (except for the one seen in Liam's flashback, which is brown).
Ambiguous Disorder: Candace shows multiple signs of having Schizophrenia and/or OCD, but it has never been officially confirmed.
Also, Baljeet. Extremely dependent on routines and clear direction, socially introverted, observant but somewhat oblivious and emotionally stunted, able to focus for long periods on repetitive behaviors, and almost child-prodigy level intelligent.
Both the titular characters too.
Ambiguously Bi: Baljeet. While there are episodes and moments where he is clearly interested in girls (Wendy and Isabella for example), other moments come across as questionable, like his unicorn game piece in "Skiddly Whiffers" and dressing up as a flower in "That's the Spirit". On November 11, 2013, Maulik Pancholy, Baljeet's voice actor, came out as gay.
Bobbi Fabulous, though "ambiguous" is a bit of a stretch...
Amicably Divorced: Charlene and Dr. Doofenshmirtz (she kept the name). He doesn't appreciate her snarkiness sometimes, and lets her have it in his songs, but they do get along the majority of the time. To the point of her calling him when she's tied up and can't pick up their daughter.
Amusement Park of Doom: The site of both plots of "Isabella and the Temple of Sap" is the "old abandoned Old Abandoned Amusement Park", where Isabella's scout troop try to retrieve rare sap, and Professor Poofenplotz tries to steal a stock of Stiff Beauty hair spray (coincidentally made from the same sap, discontinued because only the clowns of said amusement park bought it), a plot Isabella's chihuahua Pinky (who in fact is also an agent like Perry) tries to foil.
Anachronic Order: According to Word of God, the episodes' production order does not necessarily correspond to the order they take place in.
Anachronism Stew: In "It's About Time", the characters encounter a T. rex and other dinosaurs in what is claimed to be 300 million years ago. In reality, this is long before the first dinosaurs even evolved.
In the Halloween episode, Doofenshmirtz gets turned into a werecow with the udders and everything.
Animal Mecha/Mix-and-Match Critters: The Highly Unconventional Vehicle (with cheetahs muscle, a rhino horn, a giraffe neck, a monkey tail, gorilla arms, an elephant trunk and tusks, a lion mane, and baboon feet).
Including Isabella's pet chihuahua, Pinky. Working across the street busting a mad scientist named Poofenplotz for a British woman named Wanda.
At one point he arrives to the mission briefing through the neighbor's koi pond. His superior chastises the guys who installed that entrance and orders them to give the fish fedoras and make them agents - apparently that's their main way of covering their tracks.
The koi agents do show up later in the episode, saving Perry the Platypus.
During the Christmas episode, a reindeer agent is seen at the party. When Santa shows up at the end, one of his reindeer is wearing several fedoras...
Animal Talk: When the Fireside Girls are turned to bees in "Bee Story", they are able to directly talk to other bees.
Candace: Mom! Mom! Animals hate me! Linda: Oh, that's ridiculous, honey. Perry likes you!
And again in the "Across the Second Dimension": No animals in the OWCA shelter will look at her, and the fish swim away when she stands by their tank.
Contrary to the quote above, Perry himself apparently doesn't like her all that much either. In "Oh, There You Are Perry", he mocks her behind her back after she kicks him out of the house.
In his defense, the above happens in the middle of the night, so they were both cranky. He does show up randomly sleeping on her bed. It's heavily implied he woke Candace up one time to be the first one to wish her a happy birthday.He even rescues her when she accidentally blows up a cave in The Ballad of Badbeard and when she gets trapped on Easter Island..
Animals Not To Scale: Peter the Panda is about the same size as Perry, much smaller than a real giant panda.
Animated Musical: The entire show, since every freaking episode, minus a very small few from early in season one, have had some sort of music number in them.
"Rollercoaster the Musical" is a more specific example.
Animation Bump: The animation quality gradually gets better over the course of the show's run (compare the first few episodes to current Season 3 episodes), and improves noticeably for certain specials, especially the Christmas Vacation one, "Summer Belongs to You" and most of Hong Ying's episodes.
Anvil On Head: In the episode "Bully Bust," the anvil is used as part of a Mouse Trap-inspired contraption to trap Perry, being sprung up into the bottom of a large boxing glove. Later on, Perry springs to the top of the glove; Doofenshmirtz tries to follow, but hits the anvil instead. He falls, and so does the anvil.
Anvilicious: Played for laughs in the lyrics of the song in "Sidetracked".
Agent Lyla: It's a heavy-handed metaphor for how we work together!
Anyone Remember Pogs?: Doofenshmirtz was once hula hooping and invited Perry the Platypus to join. However, Perry's hula hoop was a trap to capture him.
Applied Mathematics: In the episode "Out to Launch", Phineas and Ferb are trying to get a rocket to launch using an equation (Tsiolkovsky's Rocket Equation.), and with each new attempt, Phineas modifies one of the terms. After a few false starts, Ferb points out the problem: the equation equals the square root of a bomb. Phineas changes it to a smiley face, and their next launch is successful.
How Candace deduces her brother's involvement in "The Beak":
Candace: Something Impossible + That Thing Existing In Real Life = * gasp* PHINEAS AND FERB!
She also determines how long 'soon' means (when Jeremy says he will call her soon) by dividing by Jeremy's face.
Candace: Oh, my gosh. The square root of soon is never.
Arbitrary Skepticism: In the episode "Summer Belongs To You", Buford suddenly begins to doubt that Phineas and Ferb could follow the sun around the world, thus experiencing a 40 hour day, despite spending the whole summer with them and seeing all the incredible things they've done. Buford even lampshades this.
Buford: There's nothing I've ever seen that would make me believe that you could pull this off...Except for that time machine thing and oh, and that roller coaster, and other than that, nothing. Oh, and that time you played that song and the platypus came back. Man, nature just bends to your will, doesn't it?
However, in the end, it is revealed that Buford actually did believe they could do, and probably only made the bet so that he could eat a bug.
Given the fact that Lawrence has actually seen a couple of Phineas' and Ferb's projects in person, you have to wonder about his dismissal of Candace's Cassandra Truth in "Traffic Cam Caper". The answer may be in his enjoyment in the projects that his sons do.
Arc Shape: Triangles. There's the obvious ones, such as Phineas' head, and then there's the ones that are snuck in the background to show texture in literally every episode, usually in foliage and rooftops.
"Where's Perry" Part 1 ends on massive Cliff Hanger. Perry is zapped by multiple inators and apparently disintegrated, Phineas, Ferb, Isabella, Bajeet and Buford are falling into the gorge, Candace thinks Jeremy wants to break up with her and Laurence and Linda find out that they have no reservation in fancy restaurant. All are treated as they're equally horrible.
Art Evolution: Not heavily, but the animation from later seasons is noticeably more consistent and colorful than earlier ones,especially present after the movie, with less exaggeration on facial expressions and limb movements. Candace in particular has been affected by this change.
Artistic License - Astronomy: Doofenshmirtz so much in "The Doof Side of The Moon". Lampshaded at the end, at which point he continues to be completely oblivious.
"Unfair Science Fair Redux" also plays fast and loose with astronomy. In that episode, Mars has an indigenous civilization, breathable atmosphere, a comfortable climate, and is visible in broad daylight from an ordinary telescope. It also looks quite different from the real planet, lacking the dark "seas" and giant valleys. And it's probably best not to think too hard about the twist that the Face on Mars is a damaged version of Candace's giant stone portrait.
"Escape from Phineas Tower" tries to pass off a photo of an unbarred spiral galaxy as the Milky Way. It's also surrounded by (badly Photoshopped]) stars, meaning it's being viewed from within a separate galaxy.
Candace: Stacy, do you know what they have in France? Stacy: The pyramids?
Candace: Oh, and Stacy, pyramids? Really? Stacy: Oh, I get it. Those are Belgium, right?
Doofenshmirtz too, on occasion:
Doofenshmirtz: As they say in China, Arrivederci!
Doofenshmirtz: As they say in Mexico, Dosvedanya! Down there, that's two vedanyas!
This actually seems to be something of a running joke — for example Lawrence apparently didn't know Hawaii was part of the United States, and Buford claimed the Eiffel Tower was Mexican. Albert, who knew until then that it's French, believed Buford's claim.
Art Major Biology: Who would Lawrence have to have procreated with for his child to be green-haired?
Ferb has been shown to be quite unpredictable throughout the series, so it's possible that he dyed his hair at an unusually young age.
Doofenshmirtz's De-evolution-inator. Aside from the concept of Evolutionary Levels being biologically incorrect to begin with, most of the ancestral forms that Doofenshmirtz and Perry are reverted into are rather nonsensical and inaccurate. Probably justified as "Brain Drain" suggests that Doofenshmirtz himself doesn't know what evolution actually is, only that it is "something to do with monkeys".
Ass in a Lion Skin: In the episode "Got Game?", Perry the Platypus dresses up as a dog (i.e., he wears an earband and fake tail) to infiltrate a pet shop where Dr. Doofenshmirtz has been shopping, and ends up being bought by the doctor, who is unaware of Perry's disguise.
Ass Kicks You: Zig-zagged. When Perry take's Candace's form, he appears to be doing this— he was trying to do his trademark tail slap. It misses anyway, as Candace has no tail.
Asteroid Thicket: In "Out to Launch", the boys and Candace have to fly through one of these.
Invoked in "Tri-State Trilogy of Terror" when the kids battle the evil platypus clones. They (initially) lose though, even after they request for a more upbeat tune. Fortunately, the entire story never actually happened.
Award Bait Song: "Aerial Area Rug" from "Magic Carpet Ride" is somehow both a parody of this kind of song, and an actual example.
Other, more obviously just-parody examples include "Hole In My Heart" and "Come Home Perry".
Awesome Aussie: The platypus hunter, Liam, is portrayed this way in "Primal Perry".
Aww, Look! They Really Do Love Each Other: Possibly subverted (the sibling version) as this is only one-sided with Candace towards her brothers, and her endless efforts to bust them. We see in several episodes, including "Dude, We're Getting The Band Back together", that when Candace isn't trying to bust the boys they have a fairly close, loving relationship. Also, when she 'does' bust them in "Phineas and Ferb Get Busted", we see how much Candace really cares for them, and values their creativity. Of course, all this was in Perry's dream, anyway, so it may not count.
In the two instances where she actually gets a CD of evidence to bust them, she's forsaken it to save Phineas's life (Traffic Cam Caper)/let Phineas enjoy his birthday (Phineas' Birthday Clip-O-Rama!).
In "I Was A Middle Aged Robot", Perry leaves Doofenshmirtz for another mission just before the backstory monologue. Doofenshmirtz angrily claims that this event (Perry leaving Doofenshmirtz) would someday become a backstory.
Actually becomes the subject of a Clip Show episode - Doofenshmirtz distills his bad memories into a serum that gives him evil powers. Perry diffuses the evil by reminding Doof of their happy times together.
Bad Ass: Perry the platypus, aka Agent P. Just about all the characters have their badass moments when called for, but the straightest and most obvious example would be him.
Sergei the snail.
Badass Adorable: Meap. He's small, cute, and is capable of "behaving in a manner counterintuitatively to how he superficially appears"!
Badass Bookworm: Ferb. Knocks out Buford with one pinch, can more than hold his own while teaming up with Action Girl Vanessa, and is able to build literally anything. If it weren't for Phineas, though, he'd probably sit under that tree in the backyard and read all summer.
Bad Future: In "Phineas and Ferb's Quantum Boogaloo", a version of Candace from twenty years in future goes back in time to bust the boys, then comes back to realize her actions resulted in this. Creativity has been banned, children are all stored inPeople Jars until adulthood, and, as a side-effect of her efforts to bust her brothers, Perry the Platypus was incapacitated long enough for Doofenshmirtz to take over the world. Everything is fixed by the end, but the present-day Candace never gets the hint.
Bad Liar: Phineas in "The Beak", or more specifically, while lying to Isabella. He can be seen scratching his ear every time he doesn't quite speak the truth to her. However, in that same episode, he seems to be comfortable with lying to his mother and Candace.
If Doofenshmirtz's latest inator appears just the thing to hide whatever the boys are doing, it's basically certain something else will be the cause.
The best example is from "Voyage to the Bottom of Buford", where Candace has evidence of the boys' activity on a disposable camera. Doofenshmirtz happens to have an Erase-Inator that will blank out any media the beam hits. The Erase-Inator is pointed and fires at Candace, misses the tape by an inch, hits a stop sign making the word 'Stop' disappear, so that a truck doesn't stop and crashes into a water tanker, which bursts and washes over Candace, destroying the film.
Another example is when the boys create a ski resort and Doof. has a Melt-Inator, but the resort melts once the power goes out when the inator is plugged in, even though it was fired before it was plugged in....
An even more obvious example is from "It's a Mud, Mud, Mud, Mud World". Phineas and Ferb are holding a monster truck rally, and Doofenshmirtz has literally invented a Monster-Truck-Away-Inator. Just when you start to feel all I-know-where-this-is-going and superior, the Monster-Truck-Away-Inator is transported to another dimension and the monster trucks are cleaned up in a completely unrelated manner.
In "Phineas and Ferb Interrupted" the brothers get hit by a 'Dull And Boring-Inator' and Perry spends the rest of the episode trying to build a dynamic-inator. Finally, after a battle with Doof, he shoots it- but misses, and it is destroyed. Phineas and Ferb instead return to normal with the need to save Candace's life using imagination.
In what the creators have acknowledged is one of their favorite endings, in "Attack of the 50 foot Sister", instead of just shrinking Candace back to normal, they have the universe growfifty times bigger so Candace appears normal sized by comparison.
In "Phineas' Birthday Clip-O-Rama!", Doofenshmirtz's machine seems poised to hijack footage of the boys' projects. Instead, it hijacks an instruction video playing at a construction site, setting off a series of chain events that threaten to ruin Candace's plans as usual... except Candace successfully saves the DVD containing the footage. She only destroys it later of her own accord when she hears Phineas's birthday speech.invoked
In "Flop Starz", Doofenshmirtz's robot is about to step on a building that has an advertisement for Phineas and the Ferb-tones, but Perry tampers with the wiring and makes the robot turn and go the opposite way. The building is instead destroyed because it had been scheduled for demolition to begin with.
The very first episode, after Ferb is established as a man of few words, has him going up to a microphone as though he is about to speak, only for him to make way for Phineas. This gag has since been used several other times in the series.
Happy Birthday Isabella has Stacy Hirano learning about Perry's secret and not getting her memory erased in the process.
Doofenshmirtz: Hey! Hey, this isn't as bad as I remember! ... It's SO MUCH WORSE!
It seems like Roger has been affected by Doofenshmirtz's Rude-inator in "Escape from Phineas Tower" and is about to make fun of the attending English ambassador's large mole, when he proceeds to reveal that it was an act the whole time.
Bare Your Midriff: Candace in "Comet Kermillian", "One Good Scare Ought to Do It" and "Nerdy Dancing", Stacy and Isabella during the "Disco Miniature Golfing Queen" number in "Put that Putter Away!". Also one of the background dancers during "Squirrels In My Pants".
Sherman of Love Händel did before the band broke up, and understandably refuses to after obtaining a beer belly.
Though it's often noted that the boys typically go through the proper channels needed to make their projects technically legal (except for the fort in "Thaddeus and Thor", which is why they immediately took it down after showing it off).
Invoked by Doofenshmirtz in "The Beak" when he declares himself supreme leader, hoping that people will be too dumb or lazy to question it. It works, but for entirely other reasons.
When passing himself off as an 80's one hit wonder, Lawrence goes from "Who's that?" to "I have all of his albums!" by the time he's crossed the room.
Beach Episode: A few times, but thankfully not of the overt fanservice variety. One involves the boys actually making a beach, and a couple where the crew goes to an actual beach for various activities, including trying to find the lost city of Atlantis and saving Buford's fish.
Also occasionally averted with Isabella and the other Fireside Girls when they have to do any really tough or messy jobs.
Be Careful What You Wish For: In Phineas And Ferb Get Busted, Candace busts Phineas and Ferb on building an unsafe airlift, and their mother sends them away to a reformatory school; at first, Candace is glad they are away, but it is not too long before she begins to miss them. It gets worse when she finds out how the reformatory school is run.
On the subject of Phineas and Ferb's inventions, there's the "Be Careful What You Are Building" variant, because some of these had went awry by the effects of some of Doof's inators.
The Bechdel Test: Most episodes pass. While a lot of conversations between female characters do have something to do with guys, a lot of them are general.
Beef Bandage: Doofenshmirtz's Steak Specs in "Comet Kermillian".
Beehive Hairdo: Betty Jo Flynn, the titular character's grandmother, sports one of these.
Been There, Shaped History: Though not Phineas and Ferb themselves, the Time Shift episode reveals that their ancestors apparently built the wheel, the Great Wall of China, the car, the Panama Canal, and the English language.
Behind a Stick: In the "S'Winter" song, two of the Fireside Girls keep appearing from behind Isabella, and vanishing behind her again.
Subverted in "That's the Spirit." While running away from the villagers, the were-cow hides behind a pole. While he doesn't completely vanish, it does prove, somehow, effective in that it works.
Beneath the Mask: There are plenty of confirmed cases with Perry, Candace, Suzy and Doofenshmirtz:
Big Damn Heroes: In "Hide and Seek", when Isabella is threatened by the robot sent by Doofenshmirtz, Phineas immediately comes and rescues her.
Candace does the part in "The Chronicles of Meap".
Being the most action-oriented character, Perry gets to do this a lot. In The Movie, in "Mission Marvel", in both musical clipshows...
The more action-packed episodes (such as The Movie and "Mission Marvel") seem fond of scenes where one Big Damn Heroes moment is shortly followed by another. The penultimate battle in "Mission Marvel", for instance, has Baljeet, Phineas and Ferb, Perry, and Doofenshmirtz rescue the captured superheroes before Candace and Isabella arrive to return the superheroes' powers.
Big Eater: Apparently, Buford can down an entire jar of jellybeans in under a second.
A more straight example would be the Doofenshmirtzes.
Bilingual Bonus: Dan Povenmire is a German speaker himself, which has come in handy for giving Doofenshmirtz accurate German lines (such as calling himself a Dummkopf) and even managing to get crap past the radar by basically saying "You scared the shit out of me" in German.
Also, in German, Doofenschmerz means "moron's pain".
"The Great Indoors" gives us several from El matador de Amor:
Por lo tanto su malvada hermada gemela ha sido envenenado is Gratuitous Spanish for "Therefore, your Evil Twin sister has been poisoned."
La esponja milagroso means miraculous sponge.
When this Show Within a Show is suddenly cut off, the male character is about to reveal to the female character the reason he really likes her —exactly what Jeremy is constantly being prevented from revealing to Candace in the B-plot.
And coupled with Fun with Acronyms: O.W.C.A. means "S.H.E.E.P." in Polish. Although this one's probably accidental.
The hotel Jeremy stays at while in Paris is "La Poubelle"....known in English as a 'garbage can'.
There was an episode where they celebrated Linda's brithday.
Also, there was an episode which was dedicated to Phineas' birthday in the form of a Clip Show.
"Candace Loses Her Head" celebrates Candace's birthday.
Doofenshmirtz preparing for Vanessa's birthday is the subplot in "Dude, We're Getting the Band Back Together", and Doofenshmirtz himself tries to celebrate his own birthday in "Raging Bully".
Birthday Hater: Doofenshmirtz, describing his as "The lousiest day of the year". Justified by the fact that every birthday of his has been a total disaster, including his actual birth, when neither of his parents bothered to show up.
Bishie Sparkle: Happens in "Jerk de Soleil" when Candace sees Jeremy and he gets all sparkly; given that he is her crush, it's not surprising.
Also, there is a variation: when Ferb first sees Vanessa, he sees her surrounded by various flowers.
And the third time, too.
The Flawless Girl from the TV ad that Candace and Stacy see.
Body Horror: The episode "Canderemy" centers around Doofenshmirtz's latest creation: The Combine-Inator, which he uses to combine various objects and people. While the titular combination of Candace and Jeremy is clean, humorous, and not scary in the slightest, the other ones...aren't◊.
Also, in "Phineas's Birthday Clip-O-Rama", we get a brief glimpse of his Inside-Out-Inator, which he accidentally hits himself with. It's Played for Laughs, but uggghh...
Bond Villain Stupidity: Doofenshmirtz, though that's partly because it's just how his dynamic with Perry works.
Borrowed Catchphrase: All regular catchphrases tend to be used in at least one point by other characters.
Noteworthy example is the "Whatcha' Doin'?" line. Isabella can sense halfway across town if someone else uses her catchphrase, and tends to get angry whenever someone else says it to Phineas. If he says it to her, then she'll be okay with it (as long as he says it only to her).
"Hey, where's Perry?" is another noteworthy example, said often by one time characters or guest stars (For example, Chaka Khan in Summer Belongs to you.)
Lampshaded in "Phineas and Ferb Busters":
Phineas: Baljeet, would you do the honors? Baljeet: Boy howdy! Hey — (The scene abruptly cuts to Perry's lair.) Major Monogram: Where's Perry?
Lampshaded again in "Bad Hair Day".
Stacy: Hey, where's Perry? What, I'm like the only one who hasn't said it.
Bound and Gagged: Control Freak (toon Candace). Perry is restrained every episode.
Bowdlerise: The Netflix stream of the show changes an announcer's line about Buford in "Raging Bully" from "He's missing a chromosome" to "He enjoys breaking bones."
In the "Musical Cliptastic Countdown", Major Monogram and Doofenshmirtz do this occasionally to the viewer at home (they voted, after all), but the rest of the episode is either showing the clips or advancing the unique plot of that episode.
Phineas: Hey, where's Perry? Ferb: He's making a guest appearance on a musical clip show. Phineas: Hmm... well, that's good for him.
"Mom! Phineas and Ferb are making a title sequence!"
Doofenshmirtz is hungover in "Crack That Whip" and starts to explain his latest plot:
"It all started when I was 15..." [Picture goes wavy] "No, my head hurts too much for a flashback." [Picture returns to normal].
In "Summer Belongs to You:"
Linda: It sure would be helpful if they could just make the days a little longer. [A "ding" noise signaling an idea is heard as the bottom half of the screen is covered with an "advertisement" reading "You're Watching Television!"] Phineas: Hey! Do you mind? We've kinda got a visual gag going on here! [Advertisement disappears, revealing the "ding" was actually from Ferb with a triangle.] Phineas: Thank you!
Phineas addresses the audience in "Summer Belongs to You!" with the line "No matter where we go, Ferb knows everyone!"
In "Wizard of Odd", Phineas actually lifts the screen like a curtain and talks to the audience from behind it.
In "Swiss Family Phineas" Candace is surprised to find Ferb giving a monkey a shower. Ferb says it had to be done.
In one episode Candace suggests Phineas and Ferb build a giant sling shot to get off an island. Phineas likes the idea and asks if he can use it another time.
This winds up being the solution to the Summer Belongs To You episode.
In one episode Monogram informs Perry that he's getting a vase for Christmas. An entire season later, Doof gives him the aforementioned vase at the end of the Christmas Episode.
In "The Lake Nose Monster", Doof writes "Big Laundry" on a chalkboard in his zinc-collecting vehicle and forgets what it means. He remembers what it meant in "Swiss Family Phineas".
"Day of the Living Gelatin" introduced Pinky as a secret agent in O.W.C.A. He finally gets an episode to shine in "Isabella and the Temple of Sap".
"Ask a Foolish Question" lampshades this when Baljeet remembers events on a monitor and acts the same as Isabella. A brick is the next thing that Baljeet thinks of.
Marty the Rabbit Boy and his musical blender.
In the "Hawaiian Vacation" episode, when Doof mentions that he's going to leave using his "Bo-At, or 'boat' as he is now told it's pronounced" this is a callback to "Interview With A Platypus."
Peter the Panda from mid-season one's "It's About Time!" makes an awesome return in "Meapless in Seattle". Good to know they haven't forgotten where they mentioned their characters live. The two times they did. In passing. God, I love this show.
In Tri-Stone-Area, when Phinabunk(?) and Gerb(?) are riding their newly-invented car, a caveman (named Conk) recognises them and says something like "Ahwah! Phinabunk an Gerb!" It might translate to "Oh heeeey! Phineas and Ferb!". Conk is the very same caveman from Boyfriend From 27,000 B.C..
Candace had said a few times before that when she and Jeremy get married, she's going to have a boy and a girl and name them Xavier and Amanda. Come "Phineas And Ferb's Quantum Boogaloo", guess what two of her kids are named (there's another boy named Fred, as well).
Both Candace and Doofenshmirtz have had moments where they are unable to think up a retort on the spot, only to come up with one later in the episode.
Heck, there are TONS of these. There's probably one in at least every other episode.
Bridal Carry: In "One Good Scare Ought To Do It!", Isabella ends up with Phineas in her arms in this pose upon saving him from falling from the unexpectedly-airborne haunted house.
Bring My Brown Pants: Baljeet has the tendency to lose control of his bowels when intimidated, and hyperventilate when in danger. His hyperventilation was a plot point, when it saved them from a weird urban sculpture.
Doof gets in on it once or twice, too.
Doofenshmirtz: Say goodbye to this pair of lederhosen...
Buford had this moment in "That Sinking Feeling".
Buford dressed like Cupid: Well, that's the end of this diaper.
And another in "Rollercoaster: The Musical" while on the roller coaster through downtown:
Buford: I'm glad I'm wearing trousers that are already brown!
Doofenshmirtz: I'll pay for the dry cleaning on your Rockenhosen.
Broken Record: In the episode "Mom's Birthday", Candace goes to buy her mom a cute little sun dress that they saw in the window of a store. So, she keeps repeating, "Cute little sun dress, cute little sun dress, cute little sun dress..."
In the episode "It's About Time!" at the credits, the dad keeps repeating, "Fossils! Da, da, da!"
Also happens in "A Hard Days' Knight" when Perry pretends to read one of Dr. Lloyd Wexler's books out loud; he is using a CD, which skips in the middle of a word.
Doofenshmirtz: Hmm. That's funny, I don't remember you saying "spec" so many times.
Brought Down to Badass: Once the superheroes in "Mission Marvel" get some help from Phineas and Ferb and their friends and a chance to exercise their ingenuity, they put up a pretty good fight against the villains even without their powers.
Phineas: Hey Ferb, isn't it cool how you can still see people's eyes in - Ferb, where'd you go?
Ferb: *opens eyes*
Phineas: Oh-hoh, you prankster!
By Wall That Is Holey: In "Spa Day", Candace and Stacy are helping build homes for the homeless. Canadace lets go of the wall they are holding in position so she can ogle Jeremy. She passes harmlessly through the hole for the window. Stacy is not so lucky.
Call Back: In the episode "Swiss Family Phineas", when the group is stranded on an island, Candace questions Phineas why he didn't make a giant slingshot to fling them back to the mainland. This is particularly amusing later in "Summer Belongs to You", when this is exactly how Phineas manages to arrange their escape from yet another island.
Phineas' specific line in reference to Candace's idea is "Giant slingshot... mind if we use that someday?"
In "Road Trip" when Perry briefly jumps into the drivers seat of Doof's semi "Mobile Mammal" from "Suddenly Suzy" plays.
In "Bubble Boys" Buford says he wants to float around like "a little woodland pixie". Later, in "Meatloaf Surprise", when the bouncy house takes off into the air, Baljeet teases Buford, saying "Are we going to float around like little woodland pixies?"
Parodied in the "Temple of Juachadoon" episode, where the Norm stand-in copies the slow clap the Doofenshmirtz stand-in did at the beginning of the scene, with Doofenshmirtz chastising him that "It's too early for a Call Back."
In "Fly on the Wall" Buford, Isabella, and Baljeet begin to sing "Summer (Where Do We Begin?)", with Phineas interrupting saying how they all know the song. And then wondering HOW they all know it, referring to the mind wipe at the end of Across the 2nd Dimension.
In "Gi-Ants" Doof gets his head stuck in a turkey and says that it couldn't be the first time that has happened to someone. It was how Perry defeated his counterpart in Across the 2nd Dimension.
And a quiz show variant in "Let's Take a Quiz", "where the rules are 'answer fast and answer often'"... and that seems to be it.
Skiddley Whiffers is a board game variant of this trope.
Camp Gay: Bobbi Fabulous is about as extreme an example of this trope as it is possible to get while still remaining in the Ambiguously Gay territory.
Camp Straight: Baljeet has shades of this. He has a girly voice, apparently likes rainbows and unicorns, dressed up as a daisy for Halloween, and has other generic feminine traits, but has been shown to have a crush on three girls so far.
The Cameo: Clay Aiken and Chaka Kahn in "Summer Belongs to You". Bowling for Soup in "Quantum Boogaloo". Laird Hamilton in "Hawaiian Vacation". Evander Holyfield in "Raging Bully". Kenny Ortega in "Rollercoaster: The Musical". Jamie Oliver in "Meatloaf Surprise". Kelly Clarkson in "Phineas and Ferb Family Christmas". Freaking RAY LIOTTA in "What a Croc".
Camera Abuse: In "Tree to Get Ready", Doofenshmirtz sings about the people he hates, including camera crews. At that point in the song, the scene shifts to a camcorder's perspective, which he pushes out of his face and apparently to the ground.
Canada, Eh?: "Paaaul Bunyan's! - Where the food is good (but not too good, eh?)"
"Sidetracked" is full of Canadian references.
Can't Get Away with Nuthin' : Both played straight and subverted. Phineas and Ferb can get away with just about anything. Dr. Doofenshmirtz on the other hand will be thwarted by Perry the Platypus even when he isn't trying anything particularly evil.
Monogram: "Agent P, nothing seems to be happening. Nothing from Doofenshmirtz; everything seems pretty quiet. So he must be up to something. Go!"
Caps Lock, Num Lock, Missiles Lock: Dr. Doofenshmritz frequently invokes this due to his Running Gag obsession with placing a self destruct button on everything he creates. The ultimate example would have to be when he built an army of giant robots and placed the buttons on the bottom of their feet. The army took one step and was instantly wiped out.
Captain Ersatz: The hippie that the Fireside girls meet in "Isabella and the Temple of Sap" is a reasonable facsimile of Tommy Chong.
Card-Carrying Villain: Dr. Doofenshmirtz, and for that matter probably most of his colleagues in the League Of Villianous Evildoers Maniacally United For Frightening Investments In Naughtiness (LOVEMUFFIN).
Also Mitch, who refuses to be called a zookeeper ("You're a poacher!" "Yes, that's it") because it legitimizes the whole thing.
In the Indiana Jones parody episode, Isabella carries a business card that literally says "Dirty Double Crosser".
Also Vanessa's attempts to persuade her mother that her father is an evil Mad Scientist.
And one time when Django, the son of an artist, was introduced, wherein he made a very large painting on the Unpainted Desert for his father (with the help of Phineas and Ferb, of course) and he led his father to see it but by that time, Doofenshmirtz's invention-of-the-week had already destroyed the dam and the resulting flood washed it away, thus rendering the whole thing pointless.
Occasionally happens to one-shot characters, such as the host of "Bust 'Em" and Baljeet's teacher.
In one of the Halloween episodes, he's watching a horror movie and asks, "Where's all the rock and roll music?"
The Cast Showoff: Seemingly every post-"Busted" Vanessa sighting has resulted in her character gaining a song, apparently due to Disney realizing voice actress Olivia Olson has an excellent voice.
Olivia Olson does the singing for a lot of other female characters as well— "I'm Lindana and I Wanna Have Fun", for instance, and in "The Monster of Phineas-n-Ferbenstein", she voices the backup singers. AND according to her Wikipedia page, she's also written songs for the show.
She also gets a song in the Christmas Episode, though Vanessa doesn't appear. (It's one of those "no one's actually singing, just accompanying a montage" songs.)
It helps of course that her father (Martin Olson) is one of the show's writers and does some of the music for it as well.
Vincent Martella (Phineas) and Ashley Tisdale (Candace) get their share of time in the musical sun as well, though of course, they are the main (regularly speaking) characters.
Let us not forget Alyson Stoner. Interestingly, at first it didn't look like this trope was going to come into effect for Alyson, since initially every song Isabella was involved in either kept her in the background or replaced her voice as a gag (S'Winter). However, as of the Christmas special she's been getting some really nice numbers and even sings the main part on two recent ones, and that's not even counting her rendition of "Let it Snow" from the Christmas album.
Carl's Voice actor, Tyler Mann, is a talented singer, but he didn't get to show off his chops until "Where's perry?"
Catapult Nightmare: Happened twice in "Phineas and Ferb Get Busted": once by Candace and once by Perry.
Catchphrase: Many, almost all lampshaded or subverted at some point. Often they'll be borrowed by another character, most obviously in "Hail Doofania!":
"I know what we're gonna do today!"-Phineas
Isabella is apparently very protective of this one, as evidenced during "Out of Toon" when she interrupts Buford saying it with a sharp elbow to the gut (Buford appears to fear her wrath and apologises, but she shuts him up and say "We'll talk about this later") and the Christmas Special, where Candace says it and we get a cut to Isabella making an "I sense a disturbance" face.
In "Suddenly Suzy", Isabella is visibly aggravated when first Suzy then Candace steal her "Whatcha doin'?" thunder. "Do I even need to be here?!"
The episode "Ferb TV" has a fake sit-com called "That's The Norm" featuring Suzy and Norm the Giant Robot Man. It gives Jeremy the catch phrase of "Holy Guacamole, you sure are a handful!" Yes, its just a forced as it sounds, and it is glorious.
The Cavalry: Alternate Phineas and Ferb from "Excaliferb" bring a monster army to fight Malifishmirtz's minions.
Chain of Deals: In 'Tri-State Treasure: Boot of Secrets', Candace is trying to get a rare Ducky Mo Mo collectable, but the man selling it will only trade for something that another person has.
Channel Hop: Sort of. From the second season onward, new episodes premiere first on Disney XD as opposed to Disney Channel since the show skews more towards the former's demographic, and are then shown a week or so later on DC branded as "all new".
Well, sometimes a week or two. Sometimes six freakin' months.
As of "The Wizard of Odd", new episodes premiere on Disney Channel first again, but now they're labeled brand new when they premiere on Disney XD.
It seems that in the second season a lot of the characters have undergone a fair personality development, but it's "Summer Belongs To You" that really skyrockets with deepening the characters' individualities. Phineas showing that he's not completely resourceful, getting frantic once he's realized his perplexity and showing anger and impatience for once, Candace gaining belief in herself and things seemingly impossible, Vanessa accepting her father's quirks and pecularity, Jeremy earning the ability to tell Candace about her annoying obsessive behaviour (which further led them to become an Official Couple), Isabella crossing the edge of her endurance to Phineas's ignorance towards her and revealing to be the only one able to encourage him into not giving up. Even Buford gets some screen time showing that he is fluent in French and can quote Voltaire from heart. Only Baljeet remained unaltered by the episode.
Nowhere is Phineas' characterization more apparent than from "Rollercoaster: The Musical". Instead of "We should have charged more", it's "It was sure nice to see Meap."
Consider Jeremy's mother. In seasons 1 and 2, She was a voiceless background character usually appearing nearby Linda. For season 3, they signed Jane Lynch for the character and they had to write a personality that made more sense for the actress. Try comparing the season 1 and 3 versions and you will notice different face structure and clothing.
Not to mention Jeremy himself. In episode one, he was just "the guy" Candace liked, episodes afterwards made him just "the Nice Guy who cheered Candace up". After that, the show slowly chipped away at his Relationship Sue-ness, revealing things such as the fact that he is the lead singer in a band and is very dedicated to his little sister, Suzy. Summer Belongs to You made him officially her boyfriend, and just about every episode he's been in since has given him a bit more development as a character, so now he's a Nice Guy who likes British things that is on occasion a Deadpan Snarker that messes with Candace's literal mind but still likes her just for who she is. He also, for some reason, carries a drain unclogger around.
Major Monogram. In season one, he was a very formal, authoritative no-nonsense boss who behaved in a totally cold demeanor to anyone he spoke to. Now, he's an eccentric Man Child whose mission briefings are never complete without at least one joke.
Chariot Race: In "Greece Lightning", the boys stage a chariot race through Danville's streets after learning about ancient Greece.
Charlie and the Chocolate Parody: The boys remodel the Har D Har Toy Company's factory to look like Willy Wonka's (complete with Chocolate River and Oompa-Loompa Expys, which surprises Phineas).
Badinkadinks: We will now lay waste to the surface dwellers!
Chaste Hero: Phineas is almost ridiculously clueless to Isabella's affections.
Isabella: I still need to get my You-Wouldn't-Know-Cute-If-It-Bit-Your-Leg-Off Badge. Phineas: (beat) Cool, let's go!
Of course, in "The Chronicles of Meap", Phineas built a "cute" radar and Isabella spent most of the episode claiming to be interfering with the tracking. When she finally outright says it, Phineas promptly says he already took her cuteness into account, and when disabling the "Isabella safety" the radar promptly exploded. However, cuteness is treated like a calculable measure here...
In "The Beak", Phineas indirectly refers to her as the most important person to him, but it could just be Superhero X in a nutshell.
Phineas trying to hide his secret from Isabella makes her the only character to which he seems very uncomfortable to hide secrets from.
Phineas eventually understands Isabella's feelings only after she kisses him, of course Isabella did this before their memories were wiped so he has no recollection of the event.
Cheated Angle: You almost never see Phineas and Ferb's faces from the front.
Also, Ferb's front-facing eye is always smaller than the eye behind it, no matter which side you're looking at. Whenever he turns his head, if you look closely, his eyes actually shrink and grow in order to fit this.
Chekhov's Armoury: Tiny little details in the A and B plots combine in the final vanishing of the evidence.
The writers are well aware that the viewers will be looking for this and so seldom take the obvious resolution.
Chekhov's Boomerang: In Bee day we watch Baljeet chatting with Ginger, then Ginger suddenly disappears. The explanation for the event becomes a gag in Bee Story. Then near the end of Bee Story, Baljeet's explanation of how bees dance turns out to be a lot of help to the fire side girls.
Also: Perry's picture of Phineas and Ferb. First introduced in "Where's Perry," it is used in "Where's Perry (Part Two)" to reflect the Re-Good-inator's beam at Carl, turning him good again.
Chekhov's Gunman: In "Attack of the 50 Foot Sister", the agency randomly makes a group of fish agents after their pond was drained when Perry had to use it as a lair entrance. They turn out to be crucial in helping Perry save the day.
Chekhov's Skill: Subverted in "Where's Pinky?" when we are told that the eponymous agent is "good with computers". He is in a way... well, if you consider grabbing them and using them as weapons, that is.
Child Prodigy: Phineas, Ferb, Baljeet and Gretchen from the Fireside Girls.
As Fireside Troop leader, you gotta figure Isabella counts as well.
Buford shows flashes of this, from quoting Voltaire in "Summer Belongs to You" to knowing King Wenceslas' background on the Christmas album.
Children Are Innocent: Phineas and Ferb seem to be almost completely unaware of how risky the stuff they do might be (besides helmets), and that they get their sister mad all the time. However, Ferb seems to be quite a bitmore mature than his brother....
Chuck Cunningham Syndrome: Django Brown was featured prominently in four early episodes, and was even a member of Phineas and Ferb's close-knit group of friends. After "Oil on Candace" he disappeared from the main cast, and has been seen only in a handful of non-speaking cameos.
Doofenshmirtz: What kind of plumber are you? [Perry takes off his plumber hat] Doofenshmirtz: A platypus plumber? [Perry puts on his agent hat] Doofenshmirtz: Perry the Platypus Plumber? [Perry drops his tool-belt] Doofenshmirtz: PERRY THE PLATYPUS!
Candace tries to disguise herself as "The Dangeraffe". It...doesn't work.
Clingy Jealous Girl: Suzy is very protective of her relationship with Jeremy (she even hints in her first appearance and outright shows in "Suddenly Suzy" that she's perfectly fine with Candace so long as she's well and far away from Jeremy). Not to mention that Candace flips out pretty much any time Jeremy is seen with another girl. Or a guy who kinda looks like a girl from the back, for that matter.
Clingy MacGuffin: Played for Laughs in an episode. The family goes on vacation to Hawaii and Candace finds a Tiki necklace that seemingly curses her with bad luck. She tries to get rid of it, but it keeps coming back to her. It later turns out the Tiki necklace was a restaurant gimmick, and earned her a free desert, which she turned down.
And then there is the episode that parodied The Wizard of Oz. When the Wicked Witch/Warlock of the West (played by Dr. Doofenschmirtz) demands that Candace hand over the magic boots, she replies that she would, but they've grown on her. By that, she means that they've literally grown vines on her and they won't come off. It's only after Phineas and Ferb give her a shoehorn that she's finally able to remove them.
Clip Show: "Phineas and Ferb's Musical Cliptastic Countdown", as the name implies.
A montage of past events appears in "Phineas and Ferb Get Busted".
Similarly, another montage of notable past events/episodes appears during the ending of "Summer Belong to You".
Also "Phineas' Birthday Clip-o-rama" as a more straight example. But mostly, it's within the framing device of setting up a montage for Phineas' birthday. And Doof trying to understand what makes his plans fail. Subverted somewhat by including original clips during the clip montages.
The most recent clip show was "This is Your Backstory," which is a compilation of all of Doof's flashbacks.
Clock King: When Linda commented it's been a long time ever since she and Lawrence went out together, he said it was 13 days, 22 hours and 17 minutes. When asked how he knew it to such precision, he explained it was thanks to a device on his cell phone.
In "Ain't No Kiddie Ride", Phineas and Ferb each pick the other's outfit out of a shopping bag, look at each other and quickly trade.
Cloudcuckooland: Drusselstein, from what we see of it. The residents of Patchkinland from "The Wizard of Odd" certainly push the sanity envelope as well.
Patchkin: [spits on ground] I have bad saliva! Maybe it was something that hit me.
Danville itself is also a mild example. Though it's not quite as strange as Drusselstein, it is inhabited by people who, for the most part, wouldn't be the least bit phased if a giant television screen suddenly got up and started dancing, and would gladly let an anthropomorphic platypus borrow their truck.
Cloudcuckoolander: Many members of Heinz Doofenshmirtz's family, but especially Heinz.
Lawrence - Ferb's father and Phineas and Candace's stepfather - is fairly grounded, but prone to making curious statements and not batting an eyelid at things like the TV talking back to him.
Candace definitely has her moments. For instance, there's her tendency to talk into things that aren't a phone, then not be surprised when she hears a "response".
Coincidental Accidental Disguise: In "Are You My Mummy?", Candace ends up wrapped in toilet paper like a mummy. And in "Get That Bigfoot Out Of My Face!", Doofenshnirtz ends up covered in mud and leaves and looking like a bigfoot. In another episode the two of them trade an accidental disguise of being an orangutan.
Comic Book Time: The longer the series runs, the less likely that the events are taking place within the span of a single summer vacation, especially since there are Christmas episodes.
Comically Missing the Point: P & F Quantum Boogaloo. It's bad enough that young-Candace can't get it into her head that its her obsession that makes her blind to the boy's true motives, especially when told directly by her future self (who finally learned it during her time travel trip). But this line really takes the cake.
Older Candace: (To Phineas and Ferb) And remember be nice to your sister. Younger Candace: (In something of a mocking tone) Yeah, be nice to your sister!
Doofenshmirtz, in his plan to leave "carbon footprints" all over the Tri-State Area... with a giant paper-mache foot made of carbon paper. Well, at least he admits that he has no idea what a "carbon footprint" is.
In "The Beak", Candace thought the entire thing was a game, rather than an actual super villain thinking The Beak is a superhero. In reality, even he was missing the point, as Phineas and Ferb only built the suit to get through a very dangerous skateboard ramp. The latter's missing the point can be justified because he read the news article that mistakes him for a superhero.
In "What Do It Do", Linda completely fails to understand that her situation in that episode is identical to what Candace experiences in her everyday attempts to bust her brothers.
In "Last Train to Bustville", Candace hears a speech about never giving up which inspires her to...give up.
In "Isabella's Birthday" when Stacy is watching The Grievance, she's scared of the bugs and mess the ghost girl is leaving in the house rather than the ghost girl herself.
The Comically Serious: Perry is more serious-minded and professional than anyone else involved in his plotline, only rarely smiles and often expresses displeasure at Monogram and Carl goofing around or the absurd nature of Doofenshmirtz's plots. But he's still a platypus in a hat busting a ridiculous Mad Scientist.
Comical Overreacting: One of P & F's devices accidentally split Candace into two selves: the really likes Jeremy self, and the needing to bust her brothers self. The latter got so shocked by someone not wanting to bust her brothers that she screamed and pointed in a Shout-Out of the 1978 version of Invasion of the Body Snatchers.
Candace does this a lot, actually...
Commercial Break Cliffhanger: Literally (and, naturally, lampshaded) in "Excaliferb". "Meapless in Seattle" has a similar example, as well as "Primal Perry".
Candace is examining a row of books with no visible titles Candace: Boring, dull, stupid, lame, heavy-handed and derivitive. Mom: Oh, thank you for those insightful reviews of books... you haven't read.
Compressed Vice: The episode "Bully Bromance Breakup" gives reveals a hilarious, but undeniably bizarre flaw of Phineas': If he is given an opportunity to invent something, but doesn't/is forced not to, he slowly becomes more and more panicked, curling up into a Troubled Fetal Position while listing all the things he could build, then eventually snapping and building a house out of ice just for the sake of building something and ease his nerves. This not only comes completely out of nowhere, but it directly defies the episode "The Best Lazy Day Ever", where he is repeatedly, intentionally given opportunities to build something, and calmly declines.
One could argue that deciding not to do something is doing something.
Phineas did decide to build something but was interrupted by Baljeet's unexpected declaration to manually climb a mountain and was forced to set aside his desire for a while.
Concert Kiss: Quite literally in "Dude, We're Getting the Band Back Together".
Cone of Shame: Even platypuses aren't immune. Perry had to wear one for most of the morning, which was so big that it kept him from entering his lair, and subsequently, from thwarting Doofenschmirtz.
Conflict Ball: Given that Phineas and Ferb's antics never cause permanent harm and are always swept away at the end of the episode, you have to wonder why Candace is so hell bent on busting them.
Lampshaded in the episode "Flop Starz", where the boys become one-hit wonders:
Candace: I'm gonna tell Mom. Phineas: Okay... tell her what? (beat) Candace: Ooh, I'm just gonna tell!
Conjoined Twins: In "Canderemy", we get an artificial case between Candace and Jeremy.
It's been interrupted rather jarringly multiple times, even by Doofenshmirtz himself.
The jingle has several variations depending on where the Doctor actually is. For example, at night "Doofenshmirtz Evil Incorporated! (After hours...)" And there was another where Perry finds Doof in the woods, the jingle was "Doofenshmirtz's out in the foooreeesst!" And of course: "Doofenshmirtz's Abandoned Factoryyyyyy!" They literally had to rush the ending to make it fit.
There's also "Perry Lays an Egg", when Dr. Doofenshmirtz is teasing whales, the jingle is "Doofenshmirtz holding a buuuuuuuuckeeeeet!"
Of course, when we see his "abandoned" storage facility (complete with appropriate signage) we hear: "Doofenshmirtz abandoned self-stoooooooooooooooooorage!"
"Doofenshmirtz Evil is carpeteeeeeeeeed!"
"Doofenshmirtz's ex-wife's houseinthehillssomewheeeeeere!" They had to rush that one, too...
Contagious Cassandra Truth: There's an episode where Candace finally convinces her mom that her brothers have done something bad, then she has trouble convincing Laurence.
And the episode where she gets Stacy and Jenny to help bust the boys.
Continuity Cavalcade: Good Lord Almighty, The Musical Episode. They bring back the first guy who delivered "Aren't you a little young to...", in Candace's second song she mentions several past events the boys have been involved in, the adult Candaces from "Quantum Boogaloo" show up in the background of the supermarket parking lot, and in the final number EVERY SINGLE character, animal, invention, ANYTHING the boys have encountered in the series comes to sing the final song.
Once the basis for one of Doofenshmirtz's Evil Plans in "Swiss Family Phineas" when he remembers what "Big Laundry" meant.
Which doesn't make sense seeing as how in the credits of "The Lake Nose Monster" he remembered that it meant that it was laundry day, complete with a humongous pile of clothes. Maybe it had a double meaning?
Lindana references are pretty common throughout the series. Word of God says that's the creators' "favorite thing" about Linda.
In one episode, Monogram tells Perry that the agency has been tracking Doof's online activity, and found out what he is getting Perry for Christmas (a vase). In the Christmas episode (a full season later), Doof gives Perry that same vase.
In his youth, Doof was forced to stand in the front lawn of his family's home as a lawn gnome, since they lost the real one. Doof then references the same story (with the same background) in "The Chronicles of Meap", commenting, "...you remember that backstory, Perry the Platypus." He does this in "Got Game?" as well, which is odd considering he thought he was talking to some dog.
Doofenshmirtz: Life was simpler back when I was a garden gnome.
Unless you consider he was talking to the audience.
In several episodes characters are seen humming or singing along to either "Gitchi Gitchi Goo" or "I'm Lindana and I Wanna Have Fun", true to the one-hit wonders that they are, and they're background music ridiculously often.
As mentioned in its initial episode—Flop Starz—a tinny musack version of one of these songs is played any time anybody rides an elevator.
Brick, brick, brick, briiiick, brick, brick, brick, it's fun! In another episode, Doofenshmirtz gets angry about a billboard advertising these that now is blocking his view.
In "Does This Duckbill Make Me Look Fat?", Doofenshmirtz comments that he really should have unplugged his Shrinkinator before using it as a planter. In "Let's Take a Quiz!", he still hasn't unplugged it, and it's covered in sticky note reminders to unplug it.
In "Got Game?", when Doofenshmirtz is buying a dog (Perry in a bad disguise) he tells the pet store owner that he'll pay any price since he gets a huge alimony check every month. Several episodes later his ex-wife Charlene comments that she must be paying WAY too much alimony if he can afford to build a massive ice-cream-sundae-making machine(inator).
In the second half of "Phineas and Ferb's Hawaiian Vacation", Doofenshmirtz gets stranded on a deserted island and comments on how he wishes he had a BO-AT
Doofenshmirtz: Or "boat", as I've now been told how it’s been pronounced..
Heck, this might as well be Once an Episode. Every episode has its own 'continuity' section on the Phineas and Ferb Wiki, and they're generally rather hefty.
In "Swiss Family Phineas", Candace questions how come Phineas and Ferb didn't make something to get them off the island and even suggests how they should have done it, including using a giant slingshot to launch them off the island. Guess how they got a deserted island in "Phineas and Ferb: Summer Belongs to You"? Using a slingshot to launch a giant paper plane.
Two in "Wizard Of Odd". First when Candace is being chased by flying squirrels and she screams "Squirrels, Squirrels!!" identically to how she sings it in S-I-M-P from "Comet Kermillian". Later, they play a parody of "BUSTED" (the song from "I Scream, You Scream") over the credits featuring the Tin-Man called "RUSTED".
In "Brain Drain", Doofenshmirtz mentions when Perry blew him up at Vanessa's birthday party from "Dude, We're Getting the Band Back Together".
In several episodes, Candace talks about marrying Jeremy and having kids named Xavier & Amanda. When Phineas & Ferb meet the future her in "Phineas & Ferb's Quantum Boogaloo", those are in fact the names of her kids. Oh, and Fred.
The final music number in Rollercoaster: The Musical features cameos from damn near EVERY obscure character in the series. (just a few examples are the guy with the wolf puppet from the cattle episode, the anime girls from "Summer Belongs To You", Mishti from That Sinking Feeling, and Doofenshmirtz's childhood pal Kenny).
In the same episode, when Candace come out of the grocery store, the two adult Candaces from Quantum Boogaloo are hiding behind a car.
In a recent episode, Phineas asks if they know what summer is about, and so the others begin to sing Summer (Where Do We Begin?) What made this one so epic was that everyone had remembered the song even after the memory wipe- despite having no idea how.
Continuity Porn: Every single episode contains some sort of call back to at least a few previous episodes. Seriously.
The final music number in Rollercoaster: The Musical! took this Up to Eleven. Just watch it.
If that song took it up to eleven, then Phineas's Birthday Clip-o-Rama! took it up to twelve. It's literally a Clip Show with clips from just short of every single previous episode.
And then there was "The Monster from Id" which, taking place in Candace's subconsience, mentions everything that makes Candace squirm, a sample from its song
"Were you traumatized by squirrels?/or a little girl with curls?/Do you fear the number 7?/ Does a zebra call you Kevin?"
Conversational Troping: One episode features Doofenshmirtz going on an entire rant about Literal Genies, questioning the point of misinterpreting a wish when there's no benefit for anyone to do so. He eventually concludes that the OWCA should be sending Perry after genies instead.
Cool Big Sis: Subverted. Despite the fact that Candace is quite the opposite, the boys still look up to and admire her.
Phineas points out in "Summer Belongs To You" how she's always taken part in their adventures and done so many cool things: driving monster trucks, travelling through time, becoming the Queen of Mars, and so on. To them, she is that cool.
Ginger Hirano considers her sister Stacy to be "the coolest big sister a girl could ever have".
Cool Car: The Neblington Nymph in "My Sweet Ride."
Cosmic Plaything: Hoo boy, Candace. A particularly ridiculous instance was lampshaded in "S'Winter", when Candace was riding on a snowboard with the boys. They went through a snowman, and of course Candace ended up as a comical snowman lookalike... except that she was behind the boys. They glance down at themselves and Phineas asks, "How did that miss us?" They go through a tree, same thing. Phineas comments, "That's just weird."
In The Shark of Danville Harbor, Candace is splashed with water twice. Each time the splash is a concentrated stream of water which hits only Candace. She even lampshades this the first time by saying "Okay, now how did that only hit me?". The splash must be laser-guided.
Cosplay: Phineas, Ferb, Buford, Baljeet, Candace, Irving, and Irving's brother all go to the Sci-fi Fantasy Convention in cosplay.
Phineas: We don't do this to compete—we do it for fun! Ferb: And for the ladies. *Purrs and wiggles his eyebrows*
Phineas also has shades of this in the Christmas Special:
Phineas: You know Ferb, just think of all of the wonderful things Santa does for us. And he never asks for anything in return. Wait, that's it! Ferb, are you thinking what I'm thinking? (Ferb hands Phineas a blueprint)Phineas: As usual, we're— OH! OH! Man, no! That's not at all what I was thinking! Oh, dude!(Ferb flips blueprint upside)Phineas: Oh, yeah. That's it!
Cowboy Episode: One involving a robot rodeo, another involving a cattle drive at the mall.
Crazy-Prepared: Doofenshmirtz tries to be this. His success rate tends to vary, but 99% of the time he has a trap ready to spring on Perry mere seconds after he arrives.
The Fireside Girls. Their motto is "Fireside Girls are always prepared!"
Phineas and Ferb themselves definitely qualify.
Phineas: Ferb. Water hazard ahead. Commence Operation Unforeseen Circumstance.
Carl built robot doubles of everyone in the family just in case they're ever needed.
Major Monogram: Wait a minute. You anticipated a specific situation like this? Carl: Yep. Major Monogram: Wow. That's a little creepy, Carl. Carl: Yes. Yes it is.
Perry is either this or such a Guile Hero that he can MacGyver his way out of any situation with what's on hand.
Linda sometimes wears bicycle helmets while taking a shower.
In "Norm Unleashed", Norm had a weapon ready each time Perry tried to stop him.
In Bully Bust, Buford almost succeeds and is even prepared for hungry space harpies when Candace lists it as a possible way for the boy's invention to disappear. The only things he didn't prepare for were random green rays from the sky, which he took care of by throwing conveniently placed objects to intercept the ray (including himself) and apparently parts that were sticking out of the invention that got snagged on his "Tuff Shoo Laysizz!" when he began floating after being hit by Doofenshmirtz's ray. Once again, the backyard is empty when Linda gets home, except for the kids, including Buford who is hanging from the tree by his "Tuff Shoo Laysizz!" after the effects of the ray wear off.
Creator Cameo: All the time. There are at least two Dans in Danville, Danny and a lookalike who shows up as a cameraman, doctor, and car racing commentator.
Roger: You know what they say - you can't be T'd off once you've teed off. (chuckles) That was very funny... Doofenshmirtz: What? Who says that? Roger: You know. They. Those guys over there. They: (along with ominous music) You can't be T'd off once you've teed off. Roger: Creepy, huh? I've been trying to ditch those guys all day.
Crouching Moron, Hidden Badass: Candace is prone to panicking and tends to act rather erratically in general. But time and time again she has also shown capable of amazing feats given enough motivation (most commonly when she's trying to bust or protect her brothers).
Bollywood Nerd Baljeet has had his moments. He once took out dozens of Doof-2's Normbots using the Beak suit... by sissy slapping them.
An alternate version of him from ancient China in "Doof Dynasty" also helps an alternate Buford defeat numerous castle guards, albeit offscreen. (And, unlike Buford, he wasn't even holding a weapon!)
Irving once single-handedly took out a fleet of robots in the same battle as above. And Doof once saved his daughter and her friends from and angry swarm of bees, and...lets just say, if any character on the show is depicted as a wimp, expect this trope to come into play at least once.
Crush Parade: In "Candace Disconnected," this is the fate of her new, not-to-be-lost replacement phone. Courtesy of the boys, of course.
The one in "Journey to the Center of Candace" takes the cake. Perry had Doof chained to a pipe in under ten seconds. That's what happens when you indirectly threaten Phineas and Ferb when he's in hearing distance.
The depowered superheroes in "Mission Marvel" suffer quite a few of these at the hands of the villains before they finally get to dish it back out.
Curb Stomp Cushion: It's not uncommon for Doofenshmirtz to put up a reasonable fight against Perry.
In "Meapless in seattle", Isabella usesher cuteness as a weapon to beat Mitch.
Cuteness Proximity: In "Meapless in Seattle", Prof. Yore was able to inflict this on everybody after enhancing himself with Cuteonium. And again, with Mitch, after doing the same thing. Isabella is able to do this without Cuteonium.
In his infancy, Liam's mother became distracted by a platypus this way and caused his stroller to roll down a hill, leading to his hate towards platypuses. Later, the docents at the botanical garden are distracted by Perry in the same way.
Played with when he creates the "Age Accelerator-inator", but only intends to use it for his new career as a cheesemaker, allowing him to age cheese without actually waiting. Of course, he does start using it for evil later, but only after Perry ate his entire cheese wheel.
Forget about the 'inators' he makes, Doof could make a ludicrous fortune as a security systems contractor and consultant - I mean, yes, so Perry always gets out eventually, but not only does Doof catch him in almost every single episode, he knows exactly where Perry is going to enter, and what to use to capture him!
This is also the likely source of the funding for the boys' grand projects. The majority of Danville has been in their backyard to participate in some kind of show/business/ride. At least one of these was a for-profit venture ("At The Car Wash") and the star-nosed mole left to destroy Tokyo before they could use their earnings to protect him. Surely that helped their bottom line.
And while it's implied that they didn't get paid for their toy design, they must surely have gotten some royalties for their hit song.
Nope, the corporation just stole it.
They also charged for tickets to their rollercoaster. Although, since the people who rode it were neighborhood kids, the price was probably a couple bucks apiece at most.
And of course, the lemonade stand, which managed to become a Starbucks-level franchise before the lemonade-making machine broke down.
With the mayor's permission, they installed a device on city hall that keeps tigers out of the area. They probably got paid for that.
Don't forget the restaurant and spa, both of which had customers lined up around the block.
Cutting the Knot: One of the puzzles in "We Call it Maze" involves finding out how many jellybeans there are in a jar. While Phineas, Ferb, and Baljeet tries to solve the problem mathematically, Buford simply eats all the jellybeans and types in the answer "0".
The episode "Knot My Problem" initially averts this, as the kids recreate the Gordian Knot so that they can be the first to actually untie instead of cutting it. They get most of it, until Candace, after being hit by Doofenshmirtz's -inator, eats the (licorice) ropes.