This article is about the episode. You may be looking for the song of the same name.

Removing the part in question would cause the machine to emit a ray that turns a human into a fly.

— Phineas Flynn

Buford removes a part from a tire swing the boys are building and it accidentally shoots a ray that turns Candace into a fly. Meanwhile, Doofenshmirtz is suffering from evil scientist’s block.

Episode Summary

While Candace tries to get Stacy's help to figure out what to wear for her surprise date with Jeremy, Phineas and Ferb are trying to figure out what they're going to do after their daily project's parts didn't arrive. Buford and Isabella suggest to modify some of their old inventions, but Baljeet refutes them. Phineas decides to build something new and simple, in the spirit of summer. While the kids all try to remember how they know the song "Summer (Where Do We Begin?)", Buford inspires Phineas to build a tire swing. Phineas suddenly wonders where Perry went.

Perry enters his lair and is told by Major Monogram that Dr. Doofenshmirtz is "at the shark"; Carl quickly corrects this to "at the park." Monogram sends Perry to deal with the problem, as it is much less heebie-jeebie than he thought.

While the kids are building their giant jet-powered tire swing, Phineas walks away to confirm calculations with Baljeet. Buford fiddles with the controls so as to look busy, and removes a doohickey causing the controls to emit a glowing ray. He quickly replaces the doohickey and asks Phineas what removing that doohickey would do; Phineas figures out it would cause the controls to fire a ray turning a person into a fly, pointing out that removing a different part could turn the controls into a sorbet machine.

Meanwhile, Candace realizes that Stacy's suggestion of a hair bow doesn't look good on her, and goes to remove it, but realizes that she's been turned into a fly. She tries to get Linda's attention, but her mother just shoos her away, thinking she's just a fly. Candace persistently follows Linda and accidentally gets into the car with her, hitting the back windshield as the car pulls away.

At Danville Park, Perry comes across Doofenshmirtz having a picnic to celebrate his day-off from his job. Doofenshmirtz invites Perry to join him, but the cloth gives way and traps Perry in a hole. Doofenshmirtz then reveals his latest -inator: the Feed-the-Pigeons-inator. Perry is unimpressed, but Doofenshmirtz tries to rationalize it by pointing out that feeding the pigeons is prohibited in the park, and is therefore illegal. He then sighs and tells Perry that he's suffering from evil scientist's block, having hit a dry spell during a summer that feels like it's been going on for four years. He asks for Perry's help, and the platypus immediately hops out of the trap and walks away with Doofenshmirtz.

After finishing the tire swing, the kids all test it out. After the initial test with the kids inside the tire, Phineas pushes a button that dangles each of them in individual tires, hanging from the one large tire. Everyone enjoys it.

Perry puts Doofenshmirtz through a series of exercises and paintings in order to help him break out of his block, culminating in a successful -inator.

Candace is still trying to get Linda's attention in the car, so Linda rolls down the window, causing Candace to fly out of the car. She then flies throughout Danville, eventually ending up in Jeremy's room. Listening in on his phone conversation with Coltrane, she hears him say that he's taking her to the rodeo. Candace is thrilled because she now knows what to wear, but has to leave after Jeremy tries to swat her. She immediately is forced to flee again, this time from some of the Fireside Girls trying to trap her in a jar, and succeeds, coming across another fly with a human head in the process.

The tire swing ride has ended, and Isabella proclaims it "the most fun ever." They prepare to set up for another ride when Baljeet notices "a fly with orange hair." Phineas looks and realizes that it is Candace, and that Buford had removed the doohickey. Buford messes with the machine again and changes Candace into an alligator, a squirrel (who both have orange hair) and a wheel of red cheese, before she is changed back to normal. She threatens to bust them, but thanks them as well. Buford then notices a "FLY" button on the controls and pushes it, causing the tire swing to fly into the air and its supporting pole to end up in outer space. Isabella is disappointed that the fun is over, but Phineas turns the machine into a sorbet maker and offers sorbet to his friends.

Meanwhile, Doofenshmirtz is thrilled that he has created his best -inator ever, and gloats to Perry that since it has no self-destruct feature, there is nothing stopping him from taking over the Tri-State Area. However, before he can finish gloating, the giant tire crushes his -inator.

While the kids are eating sorbet, Jeremy arrives in a suit, looking for Candace. She emerges dressed as a cowboy, having planned for the rodeo, but they are instead going to a restaurant pronounced "Ro-DAY-o." Candace laments that it must not be "dress like a cowboy and get your dinner free night," and the waiter confirms: those are Tuesdays.


Read the transcript of Fly On the Wall.


End Credits

First verse of "Fly on the Wall" (during the end credits when broadcast by itself)


Fly On the Wall title card
View the image gallery for "Fly On the Wall".

Running Gags

The "Too Young" Line


Ferb's Line

Buford: I don't get why this stuff is called sorbet. Ain't it just a fancy-people word for ice cream?

Ferb: While ice cream is made from dairy products and turned vigorously with air, sorbet is made entirely out of fancy people.
Buford: Really?

Ferb: No, not really.

What'cha doin'?


I know what we're gonna do today!/Hey, where's Perry?

Buford: Well, Hurry up and think of somethin', I'm gettin' tired hanging around here.

Phineas: That's it Buford. You can't get more summer than a tire swing. Ferb, I know what we're gonna do today!
Buford: Uh, hatch mosquitoes?

Phineas: No. Hey, where's Perry?

Oh, there you are, Perry


Perry's entrance to his lair

Perry goes down the basement staircase, stopping at the landing next to the Panic Room, opens the bottom stair, stops himself halfway down the slide after forgetting his hat, retrieves it from the stairs, and goes back down into his lair.

Memorable Quotes

Phineas: So, what should we do today?

Buford: Oh oh oh! I know! Remember when we built that super rollercoaster? How about a super-DUPER rollercoaster?
Baljeet: So we are just adding "duper" to the title?

Buford: It's an acceptable suffix.
Isabella: We did a portal to Mars. How about a....portal to Venus?
Baljeet: Only if they make SPF 12 million.
Phineas: Actually, instead of improving one of our old inventions, we should make something brand new! Something simple.

Isabella: How do you mean?
Phineas: Well, what is summer all about?
Buford, Baljeet, Isabella: (singing "Summer (Where Do We Begin?)") Summer is running through the sprinklers in your T-shirt, shoes, and...

Phineas: Yeah, we all know the song. (beat) But I'm not exactly sure how....
Major Monogram: So Agent P, change of plans. Head over to the park and stop Doof from doing the doings that Doof does . . . do.
Carl: You have a heebie-jeebie scale, sir?
Major Monogram: Yeah. You're on it.
Candace: (as a fly) Phineas and Ferb, you are so buzzzzzted!
Candace: Could this day get any weirder?

Male Voice: Hello.
(Zoom out to reveal the voice came from a fly with a human head on it.)
Candace: Omigosh, were you turned into a fly, too?
Human Fly: Who me? No. I was always a fly. I just got shot with a human-head-inator I got this thing! It's really uncomfortable. How do you walk around with these?

Candace: Tell me about it. Be glad you don't have a freakishly long neck!
Phineas: Did someone take the doohickey thing out of the thingamawhatsit? Buford?
Buford: Uh...oh no! If I catch the mug what did this....Yeah, I'm on it.
Guy in Shuttle: (Upon seeing the giant tire swing holder) Woah, that is so weird! We're in a space shuttle and the shuttle program ended years ago!
Doofenshmirtz: This is great! The best inator I've ever made! And you know what, Perry the Platypus? There's no self-destruct button on this, so there's no way you can stop me from taking over the entire Tri-State— (the giant tire swing lands on his inator before he finishes his statement) Huh. Well, like my Uncle Boris used to say, "When life's goin' well, a giant tire comes along and smashes your inator." We all thought he was crazy at the time, but now it seems rather prophetic.
Waiter: May I take your order, "partner"?

Candace: (sighs) I don't suppose it's "Dress Like a Cowboy and Get Your Dinner Free" Night?

Waiter:No, madame. That is Tuesdays.

Background Information

  • Doofenshmirtz breaks the fourth wall in this episode, by saying that he feels as if he and Perry had been battling each other for four years, a nod to the fact that this was the first episode produced for Season 4, as well as the length of the series' run.
  • This episode reveals that Bobbi Fabulous wears a wig.
  • The house that appears at the beginning of the song belongs to Buford.
  • It is revealed that Dr. Doofenshmirtz has an uncle named Boris.
  • In production order, this is the first episode of Season 4.

Production Information

  • This is the first episode to premiere in 2013.
  • This episode and My Sweet Ride is the Season 4 premiere in Indonesia and Spain.
  • In Indonesia, this episode and My Sweet Ride is aired 7 years after Rollercoaster, which is when the series officially started.

International Premieres

  • February 3, 2013 (PlusPlus, Ukraine)
  • March 2, 2013 (Disney XD Canada)
  • April 5, 2013 (Disney Channel Israel)
  • April 17, 2013 (Disney XD UK)
  • April 18, 2013 (Disney XD Poland)
  • April 24, 2013 (Disney Channel Australia)
  • April 27, 2013 (Disney Channel Scandinavia)
  • April 28, 2013 (Disney XD Spain)
  • April 29, 2013 (Disney XD Italy)
  • May 4, 2013 (Disney Channel Portugal)
  • May 5, 2013 (Disney Channel Spain)
  • May 22, 2013 (Disney Channel Brazil and Latin America)
  • May 25, 2013 (Disney Channel Poland)
  • June 3, 2013 (Disney Channel Asia)
  • June 16, 2013 (Disney XD Latin America)
  • September 2, 2013 (Disney Channel Russia)
  • September 7, 2013 (Disney XD Netherlands)
  • September 21, 2013 (Disney Channel Hungary)
  • September 24, 2013 (Disney XD Germany)
  • August 17, 2014 (RCTI Indonesia)


Error FlyOnTheWall

Bobbi's legs are missing and the bathroom is on the right position.

  • In the song, a scene pops up of a calendar on June. It folds back a month, but it shows a July calendar. It should have shown May.
  • Also during the song, when Candace enters Bobbi's bathroom, his legs are missing, and only he is inclined, while the bathroom behind him is on the right position.
  • When Isabella, Baljeet and Buford start singing, for a second, one of Isabella's eye's are the same colour as Baljeet's eye.
  • After "Summer (Where Do We Begin)" one of Phineas' shoe turns green.
  • Isabella, Baljeat, and Buford were all absent when "Summer (Where Do We Begin?)", so they either shouldn't have had it in there memory (even if the Amnesia-inator didn't take out all of the memory from the Movie), or they'd come up with the song outside ofedia, but Phineas would have remembered this (maybe the song "already" existed in Phineas and Ferb's world and they just sung it).
  • With the above, when Phineas says "Yes we all know the song" Perry's eyes are suddenly open as if in shock that they'd remember his secret, Yet Perry was absent from that scene also.
  • It would be hard to misspell "park" as "shark" because p is on the right side of the keyboard and s is on the left side. In addition, there was a letter added to the word.
  • Both Buford and Isabella mention projects neither of them were involved in. Buford mentions the Rollercoaster, but only Phineas and Ferb did that, although Isabella was a rider, and Isabella mentions the Portal to Mars, but only Phineas, Ferb and Baljeet built that. However, Buford could be mentioning the Rollercoaster in Rollercoaster: The Musical! and Phineas, Ferb and Baljeet had mentioned the Portal to Mars to Isabella at the end of Unfair Science Fair.
  • The world map in Jeremy’s room shows several inaccuracies: it had the Korean, Liaodong, Shandong Peninsulas along with the islands of Hokkaido and Iceland missing from the map, and the Mediterranean, Caspian and Baltic Seas are shown to be landmasses connecting to the mainland.
  • Flies live more than seven days.


  • The kids unintentionally reference the events from Phineas and Ferb the Movie: Across the 2nd Dimension when Buford, Baljeet, and Isabella start singing "Summer (Where Do We Begin?)", and are unable to remember where the song is from. Oddly enough, they sing a verse that was cut from the movie. This shows that they do remember the events of the movie, albeit dimly. Perry also closes his eyes when the kids change the subject, in relief that they don't remember the events of the movie and his secret agent alter ego.
  • Isabella references the portal to Mars when she suggests building a portal to Venus. After the portal to Mars broke in "Unfair Science Fair Redux (Another Story)", Phineas, Ferb and Baljeet briefly reconfigured it to go to Venus.
  • When Buford is trying to turn Candace back to normal, one of the things she gets turned into is the mantis shown during the song "She's Candace", from the episode "Candace Loses Her Head".


  • The Fly - Candace gets turned into a fly much like what happens to the main character in the story. The line "Help me" from the 1958 film adaptation is also used.
  • The Son of Man - Doofenshmirtz's painting is inspired by this 1964 self-portrait by René Magritte, depicting the artist with an apple obscuring his head.
  • How Stella Got Her Groove Back - Dr. Doofenshmirtz talks about getting his "Groove" back and getting his life in back in order which was a common phrase refering to this movie.



- Did not appear in this episode.

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