Perry is chosen to be a representative for Totally Tools, which threatens his life as a secret agent, so Sergei the Snail takes over for his mission to stop Doofenshmirtz and foil his plans to use a Mustache-inator to prank the townsfolk. Meanwhile, Candace attends a retreat to help control her obsession with busting her brothers.

!! Tropes:

* TheBusCameBack: Mandy from "[[Recap/PhineasAndFerbThaddeusAndThor Thaddeus and Thor]]" returns as the leader of the Stop the Busting retreat.
* CallBack: The "put your hand down" joke, originally used by Phineas on Ferb in ''[[WesternAnimation/PhineasAndFerbTheMovieAcrossThe2ndDimension AT2D]]'', is used here by Mandy on Candace.
* ContinuityNod: Doofenshmirtz mentions his grandfather, José Doofenshmirtz, who was previously mentioned in "Meatloaf Surprise". ("[[NoodleIncident Weird story.]]")
* CreatorCameo: Dan Povenmire appears as the man reading a newspaper who gets hit by Doof's Mustache-inator.
* CrowdChant: Due to taking Mandy's advice too far, Candace has Mandy and the girls chant "Bust!" nonstop as she heads for home. It stops when Mandy realizes what they were saying.
* DelayedReaction: Mandy realizes too late that Candace has reverted to busting mode and encouraged the other girls to bust their siblings, and this is supposed to be a ''Stop'' the Busting Retreat.
-->'''Mandy''': Whoa, whoa, whoa! What just happened?
* {{Facepalm}}: Agent P does this when everyone recognizes him dangling from the blimp.
* GoodTimesMontage: Phineas and Ferb when they spend the rest of the day with Perry after he returns.
* EverythingsLouderWithBagpipes: When busting her brothers, Candace walks in her mom playing the bagpipes and her father dancing a reel, but then his legs pop.
-->'''Linda''': [[MakesJustAsMuchSenseInContext Well, I guess that answered the inflatable legs question.]]
* FailedASpotCheck:
** There's a giant UsefulNotes/{{billboard}} right next to the Flynn-Fletcher house. Candace wonders how Linda managed to miss that billboard in particular.
** And while Candace is running home, she doesn't notice the Perry billboards as they get replaced with Sergei's picture.
* FifteenMinutesOfFame: Major Monogram tells Agent P to lay low because he is too recognizable now with his fedora, until his fifteen minutes of fame expires.
* FriendshipSong: "Let's Spend Half a Day".
* HereWeGoAgain: Sergei becomes the new representative after Perry's billboards are taken down.
* JawDrop: By Candace when she sees Perry's picture on the billboard is replaced with Sergei.
* ALessonLearnedTooWell: Candace takes Mandy's advice to heart and feels like a changed girl. The only problem is, she ''won't'' give up busting her brothers, and only used the advice to further her goal even more.
* MustacheVandalism: Taken to its most logical extreme by Dr. Doofenshmirtz's Mustache-inator, which he uses to grow actual mustaches on random strangers throughout Danville. [[ChekhovsGun Later used by Perry]] to imprint mustaches on every billboard with his image. This has the unintended side effect of offending Totally Tools' CEO, Tom Totally (who has a thick mustache), so the billboards are replaced with images of Sergei the Snail in a fedora.
* NamesakeGag: Totally Tools is named after its CEO, Tom Totally.
* OhCrap: When Candace asks where Mandy got the positive reinforcement machine, she lets it slip that Phineas and Ferb built it, but then puts her hand over her mouth when she realizes what she's done.
* RousingSpeech: Candace gives one to Mandy and the girls, having used the former's advice too well and announcing that she will focus on busting her brothers more than before, encouraging everyone else to do the same.
-->'''Candace:''' Sisters, I know what you're thinking, but rest assured, this new Candace that you see before you will not react like the crazed little girl that crawled in here just this morning.\\
'''Mandy:''' Good for you, Candace!\\
'''Candace:''' For now, I am, and will always be, an older sister who is positive and mature.\\
'''Mandy:''' That's right, Candace!\\
'''Candace:''' And I am absolutely 100% positive that I have to ''bust my brothers!'' I can see it in your eyes! You know I'm right! Sisters, will we bust our brothers?\\
'''Mandy:''' Yes!\\
'''All:''' Yes, we will!\\
'''Candace:''' Sisters, repeat after me! Bust! Bust! Bust!\\
'''All:''' [[CrowdChant Bust! Bust! Bust! Bust! Bust!]]\\
'''Mandy:''' [[DelayedReaction WHOA WHOA WHOA!!!]] ''What'' just happened?!
* ShoutOut:
** Phineas and Ferb introduce Perry the spokes-platypus dressed in black turtlenecks, a trademark of the late CEO of Apple, Inc., Creator/SteveJobs.
** The scene where Phineas and Ferb waterski in pink tutus during "Let's Spend Half a Day" is a nod to the music video for "Vacation" by Music/TheGoGos.
* SpecialGuest:
** Creator/RichardKind voices the Totally Tools advertising executive.
** The song "Let's Spend Half a Day" is sung by Kate Pierson from Music/TheB52s.
** Creator/GeorgeTakei plays the Positive Reinforcement machine.
* SplitScreenPhoneCall: Doofenshmirtz calls Monogram on his monitor to ask where Perry is.
-->'''Major Monogram''': Dr. Doofenshmirtz, that information is highly classified and strictly confidential.
-->'''Doofenshmirtz''': You have no idea where he is, do you?
-->'''Major Monogram''': [[PunctuatedForEmphasis Not. A. Clue.]]
* TropaholicsAnonymous: Candace attends a Stop the Busting retreat to get her busting addiction under control. It is not clear if Candace went voluntarily or at the advice of her mother.
* VerbalTic: The Totally Tools advertising executive says "Brilliant!" at the end of every other sentence.
* WhatHappenedToTheMouse: Phineas and Ferb disappear halfway through the episode after Perry comes back, with the rest of the focus going to Candace and Sergei.