Carl Karl is the hapless intern and cameraman of Major Monogram. He works at the O.W.C.A. for college credit.
In double episode "Where's Perry" he's accidentaly zapped by Doofenshmirtz's Ultimate-Evil-inator and turned evil, and he pretends to use the O.W.C.A. supercomputer to bring the entire Tri-State Area to its knees. But Perry's pawprint is necessary to unlock the computer. Carl tries to force him to use his pawprint but he uses a picture of Phineas and Ferb to reflect the new Doofenshmirtz's Re-Good-inator, which hits Carl, returning him to normal.