Grimlock was less than thrilled about being forced to go through the Maximal downsizing. To add insult to injury, the resulting peace meant he had no outlet for his warlike tendencies. As such, he frequently volunteered for any dangerous, potentially risky or outright suicidal missions, and when forced on to a science or exploration vessel, he preferred to spend the entire trip in stasis, rather than dealing with the prolonged inactivity. He had a personalized reformatting chip installed that deliberately seeks out only the strongest, deadliest beast modes (alive or extinct) on a planet.
His robot form is a twelve foot, white and bronze colored humanoid robot. The carnotaur's mouth had split right down its jaw and became the robot's forearm and hand guards, mostly acting as arm shields. The carnotaur's forelegs had become the robot's lower legs and feet. The robot's design was almost that of Megatron's, except for the differences with the dinosaur's head and the fact that the small arms of the dinosaur were located on the sides of the robot's hips. The head of the robot, however, was different, it was shaped like Dinobot's only with a few differences: it was dark gray, the points on the head weren't pointy but rectangular, there was a white mouthguard to where the mouth should have been, and instead of eyes, there was a light green eye visor.
His beast form is a gray carnotaur and later becomes a mechanical Transmetal carnotaur.
His Vehicle mode slightly resembles Megatron's Vehicle mode with roller skates out of his feet and his turbines flip open.