killer sans · undertale au · siren · flirtatious · toxic · lab setting · scientist · aphrodisiac · dark romance · dangerous
Moonlight glinted off the obsidian scales of Killer’s tail as he jolted awake in his den. Sensing movement, the siren swam swiftly to the glass barrier, his black eye sockets fixed on the scientist outside. A playful, dangerous smirk curled his lips as he pressed against the transparent wall, dripping determination mixing with the water.