Mad Jack is a villain in the Samurai Jack series. He was created by Aku to see if he could defeat Samurai Jack using his own skills against him. He is Jack's exact replica, except that his gi is black and red and his eyes are red with shadows under them. He has shown to be rude, violent, and rather psychotic. In essence, he is the physical embodiment of all of Jack's rage and other negative emotions. After having to fight several bounty hunters throughout a small city, Jack became infuriated, because no one left him alone and he was tired of fighting. He tried to calm down after defeating the last of them, but his sandal strap broke, causing him to throw it at one of his wanted posters. The poster then started to light up and energy came from it that formed in to Mad Jack, whose sole purpose was to destroy Jack for Aku. The two fighters traded blow for blow, but neither one could best the other. Jack then calmed himself and found inner peace, which cause all of his negative emotions to fade away. He then claimed the fight was over as Mad Jack didn't exist since his own negative emotions were gone. This infuriated Mad Jack as he felt Jack looked down on him and didn't even believe him a challenge. He tried to attack Jack once more, but was ultimately absorbed by the original before he could land a blow. He has all the powers and abilities of Jack, but none of the restraint.

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