Thrax is a cyborg alien friend of Wander, enemy of Lord Hater and one of the former prisoners of the Prison Dimension. He met Wander at some point before the episode, and he was pretty friendly with him. He appeared in the episode, "The Buddies".
He, along with the rest of the prisoners, left the prison when Sylvia beamed up the portal again. He and the rest were last seen beating up Hater.
Sometime prior to the episode, Thrax met Wander, and after that changed his evil ways. It was known he owned a book store. Later, his store was destroyed and he was sent to Hater's prison dimension, for telling Hater that his book was not selling well. He beat up Hater when he first arrived, and was the first to recognize Wander when he asked them to stop.
Through the episode, he and the rest growled at Hater whenever he tried anything bad or tried to hurt Wander. They were also seen running away from the Sand Snapper, a monster native to the dimension, and helped Hater rescue Wander.
Later, after everybody was safe, Hater revealed that he was never Wander's buddy, and the thugs get ready to pounce him before the portal opens, Wander hovering and soon being followed by Hater, who mocks the prisoners. The rest follow, since Wander considers them their buddies too, and they promptly beat up Hater. With their freedom regained, Thrax and the prisoners beat up Lord Hater one last time.
Thrax has royal purple skin with part of his skeleton being shown through a gaping hole on his chest, and he also has some bandages and injuries around it. He wears pink shorts with three lines on the right side and black boots.
He also has some metal on his body. Half of his face has a metal with one pink eye on it, and a lower jaw made entirely of metal, and his right arm has metal covering the beginning with some spikes and a black limb that ends with a mace.
He was pretty hostile to Lord Hater like the rest of the prisoners, and friendly towards Wander. However, he also seemed to most concerned for his well being, shown when the Sand Snapper attacked.