You knoow that guy, trapped in stone in the palace gardens?
That's Discord, the chaos being. He's a Drakonequus, the only one of his kind, or so we know. but of course, that is all common knowledge. it is also common knowledge about the time that the Elements of Harmony defeated him in the hedgemaze. But what is not common knowledge is the one time when one of hs backup spells, -incantations that he cast a while ago as a failsafe, if he was ever defeated- turned the ruler of Equestria into a cat.
let's sweep the history books together, shall we?