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Take a look at the image above. Amidst the darkness of the dark and shifty floating Cybertronian whatever you call that thing, there are four symmetrical greenish yellow lights. Some speculate that those lights are actually eyes nostrils and we could actually be looking at Unicron. Considering this scene features Galvatron, the revived form of Megatron done so by the planet-eating Transformer himself, the idea isn't as farfetched as it first seemed. Also, the strange 5 visible pillars stretching up past the camera's view do have a striking resemblance to Unicron's tentacle-like wings.
The floating Cybertronian technology is also speculated to be the Revenge, a ship given to Galvatron by Unicron. However, the way the ship has multiple moving parts including the pillars makes it seem less like a vehicle and more like an actual transformer itself. Age of Extinction may be a reference to the dinobots, yes, however it might just be a hint that Unicron is going to attempt to devour Earth, which would bring about the extinction of the human race.