Cyborg’s powers came out differently in Earth 1. His metal part started covering his entire body, not just some select parts like in Prime Earth. Soon he had trouble moving and even breathing. When Terra found him in Starlabs, the scientists were experimenting with him and the ship that Starfire arrived in, which was also partly where the tech for Cyborg came from.
When brought close together, Cyborg’s metal parts somehow turned into liquid and left his body, joining together with Starfire’s ship. It then turned into a giant robot that Cyborg could ride and control.
Cyborg later names the robot “Rover”, and explains that they both need to be close together all the time, or else he’ll start getting encase by a metal cocoon again.
From – Teen Titans – Earth 1 Vol. 2
