What? she doesn't look like normal? Well, that is simply because Dream got to Celestia and thanks to some nifty machine she received from chaoscroc she managed to completely corrupt Celestia, turning her into Day Breaker while programming the mare to be completely and totally obedient to her. Of course, every worthy slave needs to have a uniform and what would be better than one styled after her very own Mistress? Day Breaker most certainly doesn't mind! Now walk in line unless you want Day Breaker to incinerate you.