To defeat Perry easier in battle, Doofenshmirtz turns himself into a platypus. Meanwhile, Phineas and Ferb build a machine that turns solids into liquids, and Candace ends up turning into liquid herself.
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!!Tropes:
* {{Animorphism}}: The Platyp-inator turns people into platypuses.
* BaitAndSwitch: Isabella offers her "romantic dinner for two" smoothie (made from steak, zucchini and celery) to Phineas, but Phineas refuses. Isabella it at first offended because she thinks that Phineas doesn't feel that way about her (and he doesn't) but Phineas clarifies it is because he doesn't like zucchini.
* BirthdayEpisode: Downplayed. After Candace tells Stacy about her latest busting attempt, the former wishes the latter a happy birthday before she hangs up.
* ClapperGag: Doof claps his hands to turn the dramatic lighting off.
* CopycatMockery: Buford uses his hand to mock Baljeet's talking. When Baljeet catches on, he stops talking and takes a sip of his smoothie, but Buford puts his hand onto ''his'' smoothie's straw to mock him further.
* CrazyEnoughToWork: Doof turning himself into a platypus may sound like a useless idea on paper, but [[TookALevelInBadass he reaches a notable uptick in performance during his fight with Perry]], to the point that they reach a stalemate of tiring themselves out as opposed to Perry curb-stomping Doof; even Perry himself finds it to be more difficult to take down Doof in his new platypus form. It's only when Doof tries to resort to another inator that he loses.
* DelayedReaction:
** When Candace is changed from liquid to a bucket shaped version of herself, Buford says he likes her this way and reminds him of "[[{{Pun}} Cand-berry sauce]]". Phineas begins doing his {{Expospeak}} of how they will bring Candace back to normal, but not before [[ActuallyPrettyFunny laughing at Buford's joke]].
** Doof is relieved to be back to normal, then another Doof says he is as well, and the original Doof says, "Well, good for y—WHAAAAAAAAAAAAAAAA??????"
* FailedASpotCheck: When Mom comes into the backyard after Candace is liquefied, she somehow doesn't see the device nor the Candace puddles on the ground ''right before her.''
* MidBattleTeaBreak: Doof and Perry stop fighting to have some tea.
* MirrorMatch: Since Doof and Perry are evenly matched now that Doof is a platypus, their fight goes on practically forever to the point of exhaustion.
* NonSequitur: At the beginning, Phineas, Ferb, and Isabella are somehow discussing the Talking Zebra that Candace always sees.
-->'''Phineas:''' I'm just saying that as a non-sequitur, a talking zebra seems a little...\\
'''Isabella:''' Forced?\\
'''Phineas:''' Yeah, forced.
* NoodleIncident: Why exactly does Buford have a life-sized mold of Candace? (Apparently, even Linda knows this.)
-->'''Buford''': I got life-sized molds of ''all'' my friends.\\
'''Isabella''': I'm not sure how I feel about that.
* OrphanedPunchline: When we see Candace on the phone, she has just finished explaining to Stacy why she wears white shoes after Labor Day.
* OurSloganIsTerrible: The food truck where the gang get their smoothies is called "Exotic & Unusual Smoothies", and their motto is "Our Smoothies are not NORMAL!!"
* ARareSentence: "If anyone needs me, I'll be washing a ton."
* RearrangeTheSong: Agent P enters his lair on a tricycle through a parking garage, to the instrumental break of his theme heard on the ''Across the 1st and 2nd Dimensions'' album.
* ShowdownAtHighNoon: Parodied in Perry and Doof's platypus fight.
* SubvertedCatchphrase: "I wonder what kind of smoothie Perry would like."
* TastesLikeChicken: This is how Buford reacts when Phineas and Ferb turn his chicken into a smoothie.
* UngratefulBitch: Even after being transformed back to normal, Candace still attempts to bust her brothers.
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