Well, I've not seen this anywhere, maybe I just didn't look that hard.... But everyone seems to be assuming the dragon is a Transformer. I think it's a Quint. The non-solid look matches with the quick view of the hand that we saw in AOE.... The movie is confirmed to involve the Quints. Optimus is probably being controlled by them. The movie explains why things keep coming to Earth and we know that the Quints did so 65 million years ago. And that planet absorbing Earth doesn't look like Cybertron to me.....so possibly it's Quintessa. So yeah, 3 heads is not five and they're called Quints for a reason. Possibly they have two robot mode heads and 3 dragon heads? They had two thumbs on the hand we saw..... Alternately, if they're going the Predacon route, I suspect that the Predacons wont be Cybertronians but instead, something cyberformed from somewhere else by the Quints, intended to get rid of their rebellious cybertronians.