No two robots have ever been more unlike each other. Excellion is moody, focused and quiet, while Thundercracker loves to make noise and finds it nearly impossible to keep his attention focused on one thing - unless that one thing is exploding right when he looks at it. It's no surprise that they hate each other. Excellion thinks Thundercracker is annoying. Thundercracker thinks Excellion has no sense of humor. When they go up against each other, the fight will go on until one of them is wrecked.