Phineas and Ferb The Movie: Across the 2nd Dimension
First movie outing for the Disney Channel's Phineas and Ferb involves the pair being captured in an alternate dimension where their bumbling nemesis, Heinz Doofenshmirtz, is an evil villain.
"Phineas and Ferb, unaware that Doofenschmirtz aspires to being evil, help him to effect a portal to a parallel universe. In that universe, they discover a truly evil Doofenschmirtz who has conquered the Tri-State Area and rules with a robotic, iron fist. Ultimately, Perry must form an alliance with the usual gang and their doppelgangers to save two Tri-State Areas." (Official Synopsis)