Tournament of Canterlot charity story. Reader-driven.

Last Call is just trying to live his life. It's not a particularly hard life, but not particularly happy, either: he feels useless, irresponsible, less than a stallion. He loves his wife, with all his heart... and yet at the same time, he can't bear to even look at her.
But as a local festival rolls around, strange things begin to happen around town, and Last Call finds himself trapped in a bizarre nightmare, struggling just to survive the night as monsters that had been sealed away long ago awaken from their eternal slumber, corrupting and devouring all who dare to stand in their way.