Jack Spicer is a self-proclaimed "Evil Boy Genius" and one of the main antagonists. He specializes in robotics and controls his own robot army. In his first appearance, he met the Heylin witch, Wuya, and learned of the mystical Shen Gong Wu. He has stated several times that he has wanted to rule the world since second grade. His grandmother gave him his infamous heli-bot when he turned evil. He often resorted to sobbing in public or screaming in terror due to his many defeats.
Jack lives in his wealthy parents' basement, which he uses as his "secret" lab. He has a younger cousin named Megan. He is also a Spoiled Sweet.
Examples of Jack's "evil heroes" were Chase Young and Hannibal Roy Bean. Before these two showed up, Jack was the dragons' most formidable enemy. He looked up to those evil heroes and tried to form partnerships with them, usually ending up with him getting hurt (emotionally and physically).