That Lil' Filly is a song featured in Twilight Princess Part 1.
I...am...a...nice lil' filly, but one problem. What can it be?
I don't know. My little sister is my only filly.
My long-lost sister is so very good to me.
[Appletwirl, Puffycake, and Lightning Dash]
Oh where, oh where can Twilight Sparkle be?