(Resubmitted because I'm annoyed at seeing this shit sitting around and doing nothing. I might make it better later.)
Markus is a human astronomy student with ADHD, anger issues, and a family full of misbehaving miscreants who won't take a hint. After a nearly ugly fit of rage from our 'hero', he storms out of the house and elects to drive until he runs out of fuel, money, or both.
And then he dies. Sort of. A strange voice offers him life anew in exchange for a task: He must find a strange object called a "Chaos Orb" and bring it to a place called the "Eris Shrine."
The catches? He unknowingly gives up his human body to take on that of a Unicorn. He has one month to accomplish this task. Failure will send him right back to the land of the dead... Or so he assumes, anyways.
Markus must now master his new unicorn body, make friends, learn magic, gather supplies, find a map, and get that Orb to its destination, all while dealing with social awkwardness, culture shock, dangerous creatures, and one pony who will never cease to confuse or amaze him.
(I must state for the record that I am not a HUUUUGE brony and have not watched much of the show beyond season one. So forgive me if I don't represent characters very well. That, and I haven't written anything in years. Cut me some slack by cutting me a new one. Constructively.
Also yes, the Chaos Orb isn't a thing. I'm making it a thing because originality rocks. Enjoy. Bye.)