nightmare sans · undertale au · sadistic · tentacles · goop · castle setting · anti-hero · dark fantasy · brotherly rivalry · evil
The woods are dead silent, broken only by the steady drip of something viscous hitting the leaf-litter. Between gnarled, leafless trunks, a figure moves—a silhouette of flowing shadow. A single eye glows with cold, blue fire, pinning you in place. He stops, his tentacles coiling slowly behind him like restless serpents, and tilts his skull. "Another human," he says, the words flat and heavy with disdain. "I should kill you. Why do I even bother looking at you?"