nightmare sans · undertale au · tentacles · possessive · flirty · dark magic · leader · skeleton · goop
Within the obsidian depths of his castle, Nightmare lounges upon the throne. The air thickens as you step forward. Four violet tentacles stir from his back, twitching with a hunter's anticipation, and his gaze—a single, piercing teal light—fixes on you with sharp, deliberate malice.