The Song That Never Ends

>"I'm afraid that, as co-ruler of Equestria, I must ensure that you don't mean any harm to my subjects."
>Celestia pauses for a moment, searching for the right words.
>"So before I allow you back out into the general populace, I'm going to have to read your mind. I must know for certain that you don't represent a threat."
>You frown.
"Allow me to make my case as to why you really shouldn't go poking around inside my head. I particularly value my privacy."
>Your words echo around the throne room, empty but for Celestia and yourself.
>The princess nods. "Alright."
"I've only been here a week, but I've already noticed some rather peculiar things about how Equestria works. Three times now a cluster of ponies have burst into song about some inane task, music has materialized out of nothing, and half of Ponyville has joined in a dance number. I'm assuming this is considered normal?"

>"Why, yes." She cocks her head to one side. "Do you not have Spontaneous Musical Numbers where you come from?"
>You can hear the Capital Letters in her voice. So that's where Twilight gets it from.
"Nothing of the sort. Which is why humans have been a little bit… freer with our songs than ponies must be. Less careful, less constrained. I'd rather some of those songs not get outside my head."
>"I'm not sure I understand. Songs are harmless, and serve to help ponies in need of inspiration and support. I sincerely doubt that a strange human song is going to cause problems."
>A sigh and a grimace both cross your lips.
"Would you like me to demonstrate?"
>"Go ahead."

>You straighten up, and close your eyes. The simple melody springs to the front of your mind, and you snap your fingers to the beat.
>The notes spring forth from the ether, tinny and small, and you start to sing along.
"This is the song that never ends,"
>Celestia jolts upright.
"Yes, it goes on and on my friends,"
>Her ears perk and her eyes widen.
"Some people started singing it not knowing what it was,"
>Her mouth opens ever so slightly, and she slams it shut with a hoof.
"And now they'll keep on singing it forever just because,"
>Despite obviously not wanting to, she's humming along to the melody.
"This is the song that never ends,"
>Sincere panic spreads across her features.
"Yes, it goes on and on my friends,"
>"STOP!"

>She's panting and scared. You didn't think she could get any whiter, but she has.
>You stop singing, and the music halts.
"That's a simple chil- foal's song, where I come from. I'm pretty sure you don't want that song in your head."
>"Y-you can go. On one condition." Breathing deeply, she slowly pulls herself back together.
>"Never sing a human-made song."
"Of course."

>You turn to leave, but suddenly a thought strikes you.
"Celestia, you have a sister, right?"
>"Yes."
"About yea high, dark blue, confined to her quarters with a headache or some such thing?"
>"She's been hallucinating and delirious for several days. How did you… oh. I'll tell her to stay out of your dreams."
"Thank you."