Of course, easier said than done. You've never had four legs before, and while you've seen horses move, making each leg move with the correct timing to get a comfortable gait is another matter. Not to mention, it was bumpy enough to ride on a horse's back, but now you were part of the horse itself. It took quite a few undignified attempts before you could accomplish an awkward walk, but at least you were moving forward.
Your surroundings looked totally unfamiliar, consisting of rather deep woods. As you wove - or stumbled - your way between the tall trees, you felt even more disconcerted. You hadn't seen anyone or anything you could recognize, so where on earth were you? Were you even on Earth? How would you find your parents at this rate? Were they even here, wherever "here" is?
However, you had more pressing concerns. You had been walking for a bit when suddenly, your stomach let out a rather impressive growl. You realized your hunger, only to have your other stomach growl as well. The horse one. You couldn't decide whether to be mortified or astounded. Even if you knew where to find food, who knows what this strange body of yours would accept? Grass? Leaves? Fruits? Meat?
At that moment, your ears twitched forward. Yes, twitched. Reaching up, it was only at that point you realized your ears were slightly higher and much more flexible, resembling that of a horse. You were still processing this information when the reason for your ears' sensitivity became more obvious. The galloping sound of hooves came to a halt a few yards away from you.
A horse...with a horn? No...a unicorn! Unicorns exist? But then again, you were now a centaur, so you weren't really one to talk. Maybe this unicorn was like you? Could it help you? Could it even talk? Before you could gather your thoughts --
"This is my territory!" the unicorn snorted belligerently, pawing the ground. "Return to your own kind, now!"