Superman / Batman

After having received the help of the new Toyman in saving the Earth, Batman and Superman are concerned that he might turn to villainy. He's isolated, with only his inventions to keep him occupied and could easily tip the wrong way. They send Superboy and Robin to Japan to make him an offer to build Batman's gear. As the offer is being discussed, John Corben breaks out of Toyman's fortress in an armored power-suit. Toyman was in the process of replacing Metallo's artificial body (constructed of an alloy called Metallo, invented by the Toyman's father) However, as payback for stealing his father's work, he left Metallo's kryptonite heart intact in his new cloned body. Having fun, Toyman loans Robin and Superboy their own powered mech-suits to take John Corben down.