
Niklon's "metallic monstrosity".
The "metallic monstrosity" was the name given by Spock to a giant robotic walking vehicle constructed by Niklon. It was humanoid in shape, with a transparent dome in place of a head, from which Niklon controlled all the robots on the planet. Its body was hidden underneath the floor of Niklon's chamber, leaving only the control dome visible. Niklon had made the robot giant to make his opponents feel as small as they made him feel.
In 2265, a USS Enterprise away team freed Niklon's prisoners, who then confronted him. In response, Niklon activated the robot and used it to attack them. The conflict was ended when the Traveler used his staff to melt Niklon's robot. (TOS comic: "Dark Traveler")