Fluttershy was trotting along, having a relatively average day when:
"Oh my, I just felt something wriggling in my tail!"
She bends around to investigate, and sees but a tiny dot, climbing her hair. She brings her tail around to her front, and grabs you out of the tangle.
Grabbing quickly, but gently, as Fluttershy does.
She brings you round to her face, and you rapidly get a grasp of just how tiny you really are. Her face looks like a skyline, an inch to her seems ten yards to you!
"Oh, I've never seen anything like you before!" she whispers, "What're you called, I wonder?"
Her soft and sweet voice caresses you to answer.
"I'm... a human"
"AH! You talk?" she screams, nearly dropping you, she regains her composure quickly though, calmly stating "The only thing close to your size I've seen talk are the breezies, and you're even smaller! Oh, this is great! I- did you say... a human?"
Bringing you closer to her face, she says, before you can answer "But I thought that humans were on the other side of the crystal mirror, and any that passed through would look like us!"
"Yeah, that's the thing, I'm not... that kind of human. I come from a different place, and I have no idea how I got here. Your the first perso- err, I mean pony, I saw, and I was wondering if you could help me figure out whats going on here, or at least get me back to my normal size- ehm, I'm not normally this small"
"Oh of course, I'm sure some research with my friend Twilight could help, or maybe a trick from this alchemist Zecora." You're surprised, even for Fluttershy she seems to be taking this in stride. In any case, she tucks you in her mane, and is about to fly off to one of the two places when she mutters regretfully "Oh, how rude of me. this decision should be based on your priorities! So, what do you think, talk to Twilight to see if we can get an information on your world, or talk to Zecora and see if we can get you big again!"