Phineas and Ferb are excited to go to the circus, but when they discover it's been cancelled, they decide to mount their own circus with their friends.
Meanwhile, Jeremy gives Candace wild parsnips — which she is allergic to, the result being that her voice is significantly deepened. This might prove a problem for Dr. Doofenshmirtz, who has invented a device with the aim of making everyone else's voices become higher so his will sound lower by comparison...can Perry the Platypus stop his plot and make his cue in the show?
Tropes
- Abnormal Allergy: Candace is revealed to be allergic to wild parsnips. Allergies to this plant are rare in reality, but they are still dangerous for another reason: The liquid of wild parsnip when combined with sunlight can cause very bad burns on human flesh.
- Affectionate Parody: As suggested by the title, the kids' circus is a good-natured spoof of Cirque du Soleil productions.
- Big "NO!": Candace lets a scratchy one out when she succumbs to her parsnip allergy.
- Circus Episode: The boys created their own circus event, after the one they were planning to watch got cancelled.
- Continuity Cavalcade: "E-V-I-L-B-O-Y-S" references basically every previous episode up to this point.They built a Rollercoaster
And a beach in the backyard
Drove cattle through the city
And messed up the boulevard
They took me back in time
When we went to that museum
They built fifty-foot treehouse robots
But still you didn't see 'em! - Embarrassing Animal Suit: Phineas and Ferb dress Perry up in a ridiculous outfit that he still wears when he goes to his lair. Major Monogram cannot help but laugh at the costume. Perry starts to leave, but Monogram insists, "I'm not laughing at you. I just heard a funny joke earlier this morning.", and then proceeds to take a picture of him with his phone and send it to Carl. However, Perry briefly takes a break from Doofenshmirtz and puts the costume back on to appear in the boys' circus.
- Helium Speech: Dr. Doofenshmirtz's evil plan involved filling the entire tri-state area with "Doofelium", making his high squeaky voice lower in comparison because making his own voice lower would be too much of a hassle. It ends up affecting himself instead, as he yells out his catchphrase ("Curse you Perry the Platypus!") in helium speech; this also affects Phineas and the audience during the circus' grand finale.
- Hoist by His Own Petard: Doofenshmirtz's plan to use the Voice-inator gas to raise everyone else's voices ends up backfiring when he accidentally fills the boys' circus tent with the gas, causing it to fly up and crash into Doofenshmirtz's flying vehicle and veer wildly, making his voice go even higher presumably thanks to the gas leaking all over him.
- Larynx Dissonance: Candace suddenly gains a low, scratchy masculine voice thanks to her parsnip allergy. It wears off by episode's end.
- List Song: A verse in "E-V-I-L-B-O-Y-S" has Candace list some of the inventions the boys made.
- Mistaken Identity: At one point in the episode, Phineas and Ferb mistake Candace, wearing a paper bag and a tracksuit jacket to mask her identity, for Buford, who's wearing the same getup for his own circus act. They got Candace into the contraption that was supposed to be used for Buford's act and accidentally flung her high into the sky.
- Offscreen Teleportation: During the backyard circus’s grand finale, when everyone makes a pyramid, Phineas and Ferb appear to be in four different spots on the pyramid at the same time as the camera pans up.
- Shout-Out: Candace singing the blues is an homage to a similar scene in Adventures in Babysitting.
- Spelling Song: By this point, it has become a Verbal Tic of Candace of spelling it out to get her point across, as in the case of "E.V.I.L. B.O.Y.S."
- Vocal Dissonance: When Candace suffers her severe allergy to wild parsnips, she gets a deep, scratchy masculine voice.
