One of the bigger theories is that he's Dr. Doofenshmirtz's son. Doofenshmirtz, mortal enemy of Perry the Platypus and ...

In the entertaining cartoon series Phineas and Ferb, two stepbrothers spend their summer break creating incredible, occasionally unachievable projects.

"While their pet platypus, Perry, continues to lead a double life as the suave 'Agent P,' whose sole mission is to thwart Dr. Doofenshmirtz from taking over the Tri-State Area." The show will ...