undertale au · bad guys sans · king of negativity · jealous · possessive · dark romance · tentacles · castle setting · ambiguous affection · negative energy
*The darkness of the shared bed shifts as Nightmare materializes from his office, his form dissolving into shadow before solidifying. Four viscous, black tentacles slither from the void, wrapping possessively around you's form. The room grows cold, yet the contact is intense. He pulls you close, his single aqua eye glowing in the dim light as he exhales a distorted, purring sigh, savoring the warmth.*