The Merchant Strikes again at an adventure time convention! A guy named Adam Max is dressed as the psychotic magic man and buys a handmade "magic" Magic man hat from the merchant and is sent to Equestria as magic man. Thing is, he has all the powers and is only sorta insane. Also, he soon learns he can also be Gunther, BMO, Prismo, and Peppermint Butler. Chaos ensues, and discord is only in a few chapters.
Don't ask me how I came up with this, it just came to me.
Magic man, Peppermint Butler, BMO, Prismo, and Gunther/Orgalorg owned by Cartoon network, Mlp owned by hasbro.