Fight fight it's a platypus fight!

In “Toy to the World” Phineas and Ferb create a toy “so stupidly simple, so basically bland, so idiotically uncomplicated that it can do absolutely anything” called Perry the Inaction Figure

In “Interview with a Platypus” Phineas and Ferb build a “Perry translator” to try to translate what Perry’s chatter means but it ends up being an animal translator that works on all animals

In “Chez Platypus” Phineas and Ferb build a trendy platypus-themed restaurant named Chez Platypus that’s “fun to go to and has great food”

In “Perry Lays an Egg” Phineas and Ferb invent “a giant, robotic platypus butt” called the Platy-posterior after they mistake a bird egg as Perry’s

In “Mom’s in the House” Phineas and Ferb decide to build a giant animatronic Perry for when he’s not around called the Perrytronic 3000

In “Across the Second Dimension” they build two giant platypults to play a platypus version of catapult badminton called platypult badminton

Honorable mentions:

In “The Monster of Phineas-n-Ferbenstein” Dr. Phineastein and Ferbgor make a giant platypus monster to enter the Best Monster Contest

In “Oh, There You Are, Perry” Phineas and Ferb activate the Plat-Attractor 3000 to try to bring Perry home after he misses breakfast but they end up surrounded by random platypi

In “Perry The Actorpus” Phineas and Ferb enter Perry in an online contest and Perry becomes the Totally Tools spokes-animal but it puts his secret identity at risk after the manger decides to put a fedora on him for their ads

In “Troy Story” Ferb, Buford, and Irving use a large wooden Trojan Platypus as a decoy for an even larger wooden Trojan T-rex with laser cannons while reenacting the Trojan War

In “Terrifying Tri-State Trilogy of Terror” the backyard gang read Halloween stories while having a campout and one story is called “Invasion of the Evil Platypus Clones” that’s about evil platypus cones who originated from Buford pouring grape juice on Perry