And once again, despite having finished no projects to day, I am visited by a muse's whims.

What if the changelings won?

This wouldn't be a covert rebellion story, Star Wars style, but more like the movie Daybreakers, in which most of humanity had converted to sunlight-hating vampires, and the few humans were hunted primarily by the government exactly because there were too few of them to let the general public thoughtlessly tear apart the last of the breeding stock of the only food they could eat.

So, in this world the changelings could smell love from some distance, but not miles. And because they could also eat each other's love (but of course it was unsatisfying because they consumed their own generative output and emitted almost nothing) they changeling horde would set up towns where everyone stayed in-costume.
They would have designated changelings pretending to be ponies, and others would file to pretend to be pretending to be ponies and try to infiltrate the town of innocents.
Dropping your disguise in public would be the equivalent of shouting 'olly olly oxen-free' ; everyone would stop what they were doing to hear the words of the one with a problem, consider their response as a town, then kick them out of town to maintain a sense of propriety and mystery.

Of course, occasionally a real pony would try to hide there, thinking it was mostly real ponies, or at least half of them which was why the changelings would stay in disguise. But one wrong trip to the marketplace in the evening, and there would be no more pony.
Except this day, when our subject would sneak into what he thought for sure to be the real pony of the town, and ask how they had stayed hidden ... and after some embarrassed stalling the lone changeling, in their own home, would drop their disguise, or swap it to look like the real pony, and explain how this place worked.
Then go on the adventure of trying to sneak out the pony whose natural love could be detected through walls from fifty feet away.
And the changeling army marching through, no disguise of course, having heard stories of roaming food herds in the area.