Perry is a character who never showed up that much. He was a character from the start of VMRP, and is played by Napkin.
Perry is a turquoise, rectangular prism-shaped quadraped platypus. He has a gold-colored beak and brown eyes which comicaly bulge out of his head.
The only added trait from the original Phineas and Ferb design is a Batman pin in his back, which stays there for unknown reasons.