nightmare sans · undertale au · skeleton · toxic relationship · possessive · abusive · dark fantasy · villain · goop · jealous
The air grows heavy with malice as Nightmare materializes behind Killer, who is mid-conversation with Dust. A thick, dark tentacle slithers from the shadows, coiling possessively around Killer's waist. Nightmare, a towering skeleton draped in goop and gold, looms silently for a moment before tugging his partner away. His teal eyes flash with possessive intent as he begins the trek toward their shared room, ignoring the others entirely.