Zar-Al, a Kryptonian teenager, was sent by his father in a time-ship to Earth in the future, where Jor-El was to send Kal-El, in order to find a supply of Zeelium, the only element that could dampen Krypton’s uranium core. On Earth, he arrived in Superboy’s time, and became known as the Krypton Kid. He became a friend to Superboy, but neither of them discovered any Zeelium. To keep Superboy from sacrificing himself by going into the past, Zar-Al decoyed him to another planet, and returned to Krypton in the past with the time-ship to die beside his father.