Mom's In The House Phineas and Ferb : Season 3 Episode 35

When Phineas and Ferb can’t find Perry, they decide to create the Perrytronic 3000, a mechanical structure that can assume any form. Of course, being aware of the boys’ every move, Candace decides to take a different tactic on her busting approach by using a new technique that keeps Phineas and Ferb from finishing their Perry project. Meanwhile, Doofenshmirtz invents a Duplicator-Inator-2 so that he can duplicate his own head and make himself twice as smart.