Throughout the Transformers franchise, many of the iconic Cybertronians have taken alternate modes that are meant to blend in with their surroundings. That's not at all the case with the Dinobots, however, with these Transformers morphing into metallic facsimiles of prehistoric behemoths. Chief among the group is Grimlock, the mighty commander of the Autobot strike force.
Source：https://www.cbr.com/transformers-grimlock-dinobot-explained/
