Alphys, the most terrifying monster in the underground, has found a new test subject - a squishy, alternate version of one of her worst enemies, and now it is up to Underfell Sans to save him and get him back where he belongs. (Underswap/Underfell Crossover)

The Underground isn't the nicest place. Make one wrong move, say one wrong word, and you're dead. Needless to say things aren't easy for Sans and Papyrus, escaped experiments of one W.D. Gaster, on the run from the scientist and the rest of the royal guard. Or Baby Blaster/Handplates AU meets Underfell

When the monsters came to the Surface, you were very, very young - but you already know that, don't you? This is a collection of all the stories that happen in between or during the chapters of Bought and Sold. Following Sans, Papyrus, Melody and the Reader in their small misadventures in between chapters

When the monsters came to the Surface, you were very, very young. When humans realised they could overpower the monsters, they oppressed them, and took them as slaves. (HIATUS WARNING)