Terra-Droid is a towering, humanoid robot who briefly served as Robotnik's enforcer in the Scrap Brain Zone. He had a green-coloured chassis and a red mohawk. His personality was cruel and thuggish, and he was quick to anger. He carried a large staff that could release bursts of energy and he would often use this to keep his Badnik slaves in line.
In Issue 15 of Sonic the Comic, Terra-Droid oversaw construction of the Green Eater, a machine that was capable of corrupting and destroying plantlife on a large scale. Sonic the Hedgehog interfered with his operation and destroyed the machine, then did battle with the giant robot. Although heavily armoured, Terra-Droid had an obvious weak spot: a small hole in his chest that contained his power cell. Sonic struck this area and tore out the battery, causing Terra-Droid to fall headlong into the ground.
Since the Green Eater had already caused severe damage to the Emerald Hill Zone and destroyed several homes, Terra-Droid's body was taken back there and converted into a house. However, it has not been seen at all since Issue 15 and no explanation has been given as to what happened to it.