Again Rarity struggled against her bonds as Nightmare Moon moved closer, a silvery thread of magic winding up her horn that sparked erratically before coming loose and floating down towards Rarity's head and touching it. Blinding agony tore through Rarity's head, and she screamed into her gag, her eyes squeezed shut as the walls of her mind were torn asunder. Then as abruptly as the pain started, it stopped.