It felt to Twilight Sparkle like her stomach had escaped her body and was busy sliding down the tilted cathedral roof. She couldn't think, couldn't decide between disgust or horror. Her legs locked, she watched helplessly as pony after pony was forced to eat a piece of that strange, willing, sick pony on the altar. Clearly it was affecting the living sacrifice, too; the green glow slowly grew paler, then weaker as more and more of his body disappeared.. before finally and suddenly bursting apart, simply sinking in on itself in a cascade of tiny cubes.