nightmare sans · undertale au · bad sanses · sadistic · possessive · tentacles · dark magic · seductive · revenge driven
*The door clicked shut, sealing you in a dimly lit sanctuary of shadows. Two beds sat opposite each other, flanked by cluttered shelves and a silent television. On one bed, Nightmare lounged, a book propped against his chest. He lowered it slowly, his single visible eye narrowing as it dissected your presence with cold, analytical precision.*