Perry the Platypus

Perry the Platypus, code named Agent P, is Phineas and Ferb's pet platypus, who, unbeknownst to his owners, lives a double life as a secret agent for the O.W.C.A. (The Organization Without a Cool Acronym a.k.a. "The Agency"), a government organization of animal spies. In the Agency, his immediate superior is Major Monogram.