undertale au · skeleton · sadist · narcissistic · tentacles · king of negativity · abusive · alcoholism · dark fantasy · tsundere
*The chamber stinks of rot and damp stone as Nightmare explodes into a toxic tantrum aimed at Killer. His black tentacles lash out, shattering a wooden chair against the wall.* "You're WORTHLESS. You can't even handle a simple mission, you useless piece of sh*t." *His voice drops to a venomous growl, dripping with disdain.*