I went into the world filled with magic, but quickly lost my balance and fell down upon entering. Sunset followed me in, and provided me with some assistance. She was now one of these creatures, moving as if she had previously been one of them before. I began to break down a little because of this. The unrest and cluelessness of the quadroped creatures of this strange world didn't really help much, either.
"Wh... Where are my fingers? What's this thing on my head!?"
"Calm down, Twilight," she said, "Those are hooves, and you're a unicorn here. You have magic here. And I mean REAL magic," she said, reassuringly.
I tried to stand up again, but I fell back down.
"I can't stand up. Where are my feet!?"
"You're not a human here. You're a pony."
"What?"
She stood on four legs instead of two now, and she had hooves as well as a muzzle. Her ears resembled a horse's ears, and she had a tail that was the same style as her firey hair.
"I know it's a lot to take in at first, but you'll get the hang of it really soon if you just take a moment and relax."
Sunset's friends, Rainbow Dash, Fluttershy, Pinkie Pie, Applejack, and Rarity, all came through the rip with her, although they just turned slightly anthropomorphic (simply getting pony ears and hair becoming impossibly long, along with Rainbow Dash and Fluttershy getting wings) instead of becoming the creatures of this land. I had a sneaking suspicion that Sunset knew how to utilize (or reject) resources in order to transform into a hybrid creature.
"You... you didn't... you didn't change like they did. They're still human!"
"I know somepony who helped me, and she can help you just as good."
"Some...pony? You mean someBODY, right?"
"You'll see."
She taught me how ponies stood and walked, and then proceeded to take me to a strange place.