The skeleton brothers, Sans and Papyrus respectively, are the only remaining inhabitants of Snowdin Village, and their home stands apart from the rest of the derelict shanties that still stand within the small town, well kept and glowing with electricity. The hum of a generator can be heard, when approaching the home, and the twinkle of Gyftmas lights still shine from the beams of the large, two-story house. All the windows have been neatly boarded up, however, and the wood of the porch has been disturbed, transformed into an intricate, fatal trap that will spring unless a secret button is pressed before stepping onto it.
Within, the brothers' home is kept tidy and warm yet, through Papyrus' efforts; the furniture, far more beaten and worn than before, stands where it always did, and though the fridge holds far different fare than before (the spaghetti is long gone, replaced with hanks of meat you are better off not knowing the origin of), all seems well, should you not venture into the darkest corners.
For if you looked more closely, you would spy dark red stains in the carpet that could not be scrubbed out, cracks in the walls that have far more violent origins than simple accidents, and far from welcoming grins from the inhabitants. Chains hang from the posts of Papyrus' bed, unexplained and scraped with what appear to be claw marks, the front door bears five more locks on its inside, and the door to the basement, once only secured by a simple padlock, is now impossible to open, boarded up and strung with thick chains.
There is a door beneath the stairs, untouched and hung with a "Baby is sleeping" sign, that opens to a baby's room, untouched and covered in dust, and though Papyrus' room is largely unchanged, Sans' has suffered from severe neglect and clear depression, littered with trash and gnawed bones and pocked with holes and grooves sliced into the walls.
The shed outside the house, once a place of holding for unruly citizens but mostly used for unneeded tools, now holds buckets upon buckets of dust, the icy, frigid walls strung with still moaning, bleeding monsters and cooling strips of meat. Should you find your way into the shack... you likely won't live to escape it.