Toyman, or Winslow Schott, is a Superman villian who uses toy-based or toy-themed devices and gimmicks in his various crimes.
At the behest of Oracle, Stephanie investigated Toyman's warehouse to discover he was holding and torturing the Kryptonite Man. She met up with Catwoman who hoped to collect Kryptonite Man for The Penguin. Toyman's robot, who Steph dubbed "Toyboy" snuck up on the two women and overwhelmed them. Stephanie was subdued by multiple miniature robotic superheroes, and Catwoman was tasered by the robot himself. Toyboy dropped the two women into the Gotham river in a crate, leaving them to drown.
However, Stephanie was rescued by Supergirl and the two decided to team up to take Toyman down. He once again attacked Steph with robot superheroes and Kara with Kryptonite laced robotic dinosaurs, but Stephanie held her own this time and Kara smashed Toyboy's head in. Toyman was then revealed to have teamed up with Mr. Freeze, but Stephanie disabled his weapon and lamented that Kara "took out Toyboy" because she "owed that little jerk".
Toyman ran in, very distraught his robot had been broken. Yelling at the two heroes and calling them "aliens" he quickly activated his humongous composite Superman/Batman robot. It grabbed Stephanie and blasted Kara with Kryptonite. Stephanie managed to call in a "code black" (highest level threat) to Oracle before the link was severed. Oracle called in Superman and Batman.
Batman made the robot drop Stephanie and Damian rescued her before she could splatter all over the ground. Together, Damian and Steph went to attack Toyman and Mr. Freeze. Toyman yelled that the children should have never gotten involved, because he "abhored violence against children" and now they were forcing him! Stephanie yelled, "Not so tough without your little toy army, are you? Give me that!" and she made a grab for his remote. This caused Toyman to drop the device and it shattered. Toyman was distraught, saying the navigation codes weren't implemented yet. When Stephanie shook him and yelled, "What are you talking about? What navigation codes? ", he revealed that the device was supposed to navigate the robot to "destroy New Krypton" and now the robot was going to detonate here. However, Superman and Batman stopped it.
Later when Superman and Batman came, they found Toyman stuttering and acting strange. Stephanie said, "We didn't hit him THAT hard." It turned out the man was just another of Toyman's robots!
For more about Toyman, see here.