You are...you can't remember, so lets just go with Anon. You are Anon, and you have arrived upon Equestria as the result of a magical spell cast by Twilight Sparkle...your new roomate.
Twilight manages to turn herself into a draconequus - now the only one who can help her learn to control her new chaos magic and change back is Discord. What could possibly go wrong?
Dreams and Nightmares... they can open a gateway to one's true calling if they are properly understood. I know they did for me, and I wish to share these experiences with you, so you too may understand.