What if Grimlock starts off as a regular vehicle.
Things get heavy when the Cons and the evil human scientists create and unleash a giant Cybertronian Dinosaur and has it attack China.
The only way the Bots have a chance of beating that thing is if one of them scans the prototype T-Rex from the lab where the creature was created. Grimlock volunteers and becomes a Dinobot.
What do you think?