Big Brother Spy is a Phineas and Ferb Fan Fic series created by waterphoenix21. It's an Alternate Universe where Perry the Platypus isn't Phineas and Ferb's pet platypus, but instead, their adopted older brother.
The main series takes place after the original summer, showing the new adventures Perry goes on and the friendships he forms. It can be read on AO3 here
. So far, the series consists of...
- Monty's Master: Summer Break is finally over, and as Perry sees his younger siblings off to a new school year, Monty Monogram begins his apprenticeship as a field agent. And what better master than OWCA’s top young agent himself? In other words, Major Monogram pulls the strings once again and assigns Perry another mission that may or may not require more than what he had signed up for.
- Secrets of the Platypus: When Vanessa starts her OWCA internship she is surprised to learn of the fearsome reputation surrounding her father’s former nemesis. And once she is assigned to become Perry’s personal assistant, she decides she wants to know more about him beforehand. But trying to stitch together the pieces of Perry’s double life turns out to be more difficult than she had expected, especially since neither OWCA nor the Flynn-Fletchers seem to know his full story.
There's also a spinoff series called Big Brother Perry In... which rewrites episodes of the original show with human Perry in it. It is also available on AO3 here
. So far, the series consists of...
- Elementary, My Dear Stacy: When OWCA partners with the British Spy Union, Perry must team up with an old-fashioned spy. And because Agent Double 0-0 insists on treating him like a child and criticizing his style, Perry decides to be petty about it and act as bratty and immature as Agent Double 0-0 expects him to be.
- I Scream, You Scream: Isabella's tonsillectomy leaves Perry worried and distracted during his newest mission. Luckily, Dr. Doofenshmirtz fails miserably without him even having to lift a finger. Vanessa, however, has a few things to say about Perry's methods and how he made her look crazy in front of her mother.
This fic includes examples of:
- Adaptation Expansion: The first few chapters of Secrets of the Platypus explores Vanessa's internship at OWCA, whereas in the original show, she's revealed to have taken an apprenticeship in the Season 4 finale with no explanation, and it's dropped come Season 5.
- Adaptation Personality Change: In the original show, Monty Monogram is shown to be chill and laid back, though willing to take action when necessary. Here, he's easily excitable, impulsive, and stubborn.
- Adaptation Species Change: Whereas Perry was a platypus in the original show, here, Perry is human.
- Almighty Mom: Time and time again, Linda chews out Nigel and Monogram for getting Perry hurt.
- Animal Motifs: Fittingly, Perry's spirit animal is the platypus.
- Disneyland Dad: Nigel is a downplayed example of this trope. While he does try to be a good dad to Perry, he does this by buying him a lot of toys and taking him to sports games.
- Flashback: Secrets of the Platypus serves as a prequel explaining Perry's upbringing.
- Happily Adopted: When he was around six years old, Perry was adopted by Linda Flynn and her then husband Nigel.
- Heroic Sacrifice: Perry's biological mom dies in a forest fire trying to save lives from it.
- I Work Alone: Early on, Perry is shown to not like working with others, preferring to go on solo missions, but over time, he does become more willing to collaborate with others.
- Like Father, Like Son:
- Nigel is cheerful, creative, and can invent things, just like his son, Phineas.
- Linda is overly protective of the people she loves, just like Candace.
- Parental Neglect: Nigel devotes most of his attention to Perry, and is shown to be neglectful of Candace.
- Lonely Rich Kid: Averted. After Perry loses both of his biological parents, he's initially taken in by his rich grandparents (on his father's side), but when he sees how poorly they treat their pet bird, he releases it, much to his grandparents' anger, so he's sent to an orphanage, and eventually adopted by more loving, not rich, parents.
- No Hugging, No Kissing: The author has stated that unlike most Human!Perry AU fics, they have no intention of pairing Perry and Doof together, and that Perry is aroace in their fic.
- The Matchmaker: In Monty's Master, Monty tries to set Perry up on a date. Because he's aroace, Perry isn't happy with it, though he does remain friends with the girl he was set up with.
