You stumble, fall, pass out, come to senses – and get a horn (or wings, or even both wings and a horn, if you haven't had any of them before). The most uncommon story happens to a very common pony, who is by no means ready to such a turn of events.
The story "Hard to Be an Alicorn" was originally written in Russian by Hiux and Romuald. It was translated into English by me with Hiux's permission.