"Humans are not magic. Or, to put it another way, humans are not-magic. Right Panker Poi?" - You
"STOP CALLING ME THAT" - Pinkie Pie

What if humans were immune to magic, completely unable to be affected by it? Newly arrived in the magic-saturated land of Equestria, and unfamiliar with most things here, you decide to test the limits of this immunity by messing around with your new-found pony friends. Thank goodness you speak their language.