|The Venture Bros. character|
|Aliases||"Cheetah-Man" (as referred to by voice credits)|
|Relatives||Unnamed scientist creator (deceased)|
Inability to climb trees
Toru (Friend and comrade, deceased)
Scientists, the Venture Family, Sgt. Hatred
According to Venturestein's description, Karl was created in a lab by "bad scientists" and subjected to torturous experiments, which shapes his perception of scientists to this day. Like many lab-created creatures human society calls "abominations", Karl was rescued by U.R.G.H. and taken into the fold of their revolutionary army.
After the Venture Family crash-lands in Puerto Bahia, Karl leads a small party of soldiers to capture Sgt. Hatred and Dr. Thaddeus "Rusty" Venture. (Hank Venture escapes their notice, having used a jet pack to escape the crashing X-1.) Following the capture, Karl angrily demands that Venturestein allow them to kill the outsiders because Dr. Venture is a scientist and to avenge the death of Toru, the pteranodon that had brought down the X-1. Venturestein persuades Karl to go outside and calm down, though Karl peels in the corner on his way out. Venturestein notes to Venture Karl's tempestuous past.
Later, Karl is among an angry mob of protesters formed in front of Venturestein's pyramid demanding change and the deaths of Hatred and Dr. Venture. Karl posits that he should become leader, though his suggestion is cut off by worried discussion of "the Bat". (This is actually Hank, who has undergone a chocolate-induced psychological transformation into a guise resembling the character he admires so much.) Karl forms a hunting party from his fellow angry protestors and leads them into the jungle on Hank's trail.
In the jungle, Karl discovers Hank's campsite and thereby his true nature. Despite Karl's assertion that the Bat is simply a boy with a tummy ache, Hank momentarily strings up Karl from a tree, takes down the rest of his followers, and escapes capture. Moreover, Hanks frees Hatred and Dr. Venture from their cell. After Karl discovers the empty cell, he calls his hunting party again and gives chase. On the way, Karl discovers the nonfunctional J-Pad, having seemingly been rendered useless by Hank discarding it in the swamp.
Karl and his followers catch up to the Ventures on the beaches of Puerto Bahia, where Karl mocks Hank for leaving the J-Pad in the water. As they advanced on the Ventures, they are interrupted by the arrival of H.E.L.P.eR., whom is heavily armed and loaded for bear. Dr. Venture orders the robot to kill all of the abominations, but he is interrupted by the arrival of boats filled with abomination immigrants and a helicopter carrying congresswoman Marsha Backwood, whom quickly takes charge of the situation. Marsha notes the fallen J-Pad and asks if anybody drops it. It explodes in her hands. Dr. Venture notes he "can fix this", ending the episode as the end credits roll. In the post-credit epilogue, it is revealed that Marsha has been remade into one of the -steins and represents the Abomin-Nation at the U.N. Dr. Venture and company are shown to be OK, having perhaps escaped doom by significantly helping the cause of U.R.G.H.
The exact outcome of Karl's aspirations, to overthrow Venturestein, if he ever enacted them, are not specified.