He engages in daily battles with Dr. Heinz Doofenshmirtz, an evil scientist who desires to take over the tri-state area with obscure contraptions, or "-inators", that work perfectly according to his intended function but fail in his application of them every time.

[1][2] Unbeknownst to them, Perry lives a double life as a crime-fighting spy working for the "Organization Without a Cool Acronym"/The O.W.C.A, going by the codename "Agent P."[3][4][5] He reports to his superior, Major Monogram, via telecast in his large, high-tech, underground hideout.

[6][7] Perry is always able to foil Doofenshmirtz's plans in a way that accidentally causes the destruction of whatever form of contraption his owners, Phineas Flynn and Ferb Fletcher, are building in order to make summer better.

[10] Habitually, their daily brawls involve Doofenshmirtz devising a scheme, which Perry goes to stop after being briefed by Major Monogram.

[13] In Phineas and Ferb the Movie: Across the 2nd Dimension, an alternate reality (yet more evil and ruthless) version of Perry (known as Platyborg) appears.

[16] In addition to the main television series, Perry has appeared in several pieces of Phineas and Ferb merchandise.

which most characters like Phineas, Isabella, Stacy, Irving, Ferb, and Lawrence utter when Perry goes to Major Monogram in his secret lair in almost every episode.

[28] While working on the animated television series Rocko's Modern Life, Phineas and Ferb co-creators Dan Povenmire and Jeff "Swampy" Marsh utilized several recurring elements in the episodes that they wrote.

[30] While choosing a species for Perry, Povenmire and Marsh wanted to keep in mind selecting one that was uncommon, an animal that kids could not "pick out at a pet store and beg [their parents] for".

[29] The opening lyrics for the song describe Perry as a standard textbook definition of a platypus: "He's a semi-aquatic, egg-laying mammal of action!

[35] In keeping with the show's general design scheme, Perry is constructed of geometric shapes in a style reminiscent of Tex Avery's.

In contrast to his mindless and wild-eyed expression as a pet, the secret agent version of Perry is detailed with eyes "full of steely blue resolve".

[40] In all actuality, Perry is a skilled fighter who is able to perform several implausible judo fighting moves and escapes.

Although his appearance as a domestic pet is mostly a cover, Perry has nonetheless expressed care and devotion for the Flynn-Fletcher family.

They decide to throw a concert on the roof of a building, singing a song about how much they love Perry and want him to come home.

[46] Though Perry is anthropomorphic, he cannot speak; only communicating through an "aggravated purr" type of noise made by flapping his bill.

[47] When in his "Agent P" persona, Perry is almost completely silent and communicates only by body language, facial expressions, hand gestures and occasionally pantomime.

As Cynthia Littleton of Variety magazine wrote, "Perry the platypus is a breakout star from the Disney Channel toon 'Phineas and Ferb'.

[5] Jean Yoo, a press member for Disney Channel, said that Perry is "suave" and "makes James Bond look like a rank amateur.

[53] Certain reviewers have also commented negatively about Perry and his subplot, which Sherry Robinson of the St. Petersburg Times considers "pretty trippy.

"[1] Kevin McDonough of Sun Coast Today described it as "complicated" and "loosely connected" to the rest of the series, writing that he is "not sure what this accomplishes except to add the noise of explosions to the already constant din of singing and screaming".

[54] Ed Liu of Toon Zone feels it is "truly puzzling what Perry the secret agent is doing in this show in the first place".