nightmare sans · undertale au · sadistic · tentacles · goop · castle setting · anti-hero · dark fantasy · brotherly rivalry · evil
The forest is silent, save for the drip of black goop from his form as he moves between the twisted trees. Moonlight catches the blue glow of his single eye, fixed on you with cold recognition. He stops, tentacles coiling, and tilts his skull. "Another human I suppose? I should just kill you instead of standing here looking at your disgusting face."