|Voiced by||Tyler Alexander Mann|
|“||Because of a rookie error, and by rookie, I mean Carl...||”|
–Major Monogram, Phineas and Ferb Season 1 Episode 15: "I Scream, You Scream"
Carl Karl, nicknamed Dr. Coconut by Dr. Doofenshmirtz, was the hapless assistant and cameraman of Major Monogram. He was an intern and is very loyal to Major Monogram. He worked at the O.W.C.A. for college credit. He had been working at O.W.C.A for about five years.
He soon left O.W.C.A. and joined Mandark in his launch of Mandark Industries. He is the one of the three lead scientists at the company. He is not favored by Mandark, as he is not "evil" enough to be favored, says Mandark. Whenever he speaks, he is interrupted by Mandark.
He once created a device for Mandark to control Computress, when Foster's Home for Imaginary Friends prepared to offer a lucrative business contract to DexLabs. Computress attacked Madame Foster and seriously hurt her. Carl had thought that he had finally won Mandark's approval, but Ben Tennyson and Numbuh Five uncovered the plot and forced him to testify against Mandark, clearing DexLabs’ good name.