As the filming crew rolls out (inside joke 1) of Chicago, this bit of footage claims to have spotted Sentinal Prime. The security guard keeping people at bay (inside joke 2) even tells us as much. Said guard also claims that Sentinal is "Optimus Prime's father". As far as I can see, it resembles more of an Ultra Magnus Animated style vehicle. Keep in mind, we are being told this by a security guard, not a writer or Bay himself. I wonder if he was handing out large pinches of salt too.....