Starscream, the double-crossing backstabber who earned himself his own trope over at TVtropes.com, would have probably made a great antagonist on his own. But he’s dead. So we’ll try Swindle, ANOTHER double-crossing backstabber (well, he’s more of a hustler looking for a quick buck, but the fact that he's willing to create disharmony and conflict to do so might also work as well). ALTERNATE MODE – a pirate ship (as seen here: Transformers Pirates Ship Trailer - YouTube) VOICE ACTOR – Johnny Depp or Geoffrey Rush, I don’t think I can see any other fulfill that role. And isn’t Swindle in his own way a pirate? ROLE – he’d play off the Autobots, Decepticons and humans against each other, and then side with whoever won. And when they ALL come for him, he makes a getaway, never to return within Earth’s Moon for fear of getting caught and shot (so much more fitting than getting killed). Please excuse me, I have pirates on the brain but I think they could work.