Phineas and Ferb - Season 3 Episode 36
Perry the Actorpus

The executive of Totally Tools oversees a contest to find the companys "spokesanimal", and Perry is crowned the winner. However, the victory puts Perrys secret identity in jeopardy, forcing Major Monogram to appoint Agent S as a temporary replacement, but when Dr. Doofenshmirtz sees his new nemesis is Sergei the Snail, he mistakenly underestimates his new opponent. Meanwhile, Candace has been welcomed into Mandys "Stop the Busting" retreat, which aims to teach Candace to control the urge to bust her brothers through positive reinforcement.