Papyrus is sick with a seriously bad virus unique to skeletons. All Sans wants to do is take care of his little brother but because of his low HP he is in danger of catching it and getting terminally ill, so they have to be kept apart from each other whilst the virus runs it's course...something that Sans cannot stand...

The people who love him come to realise Sans may be hiding something from them. (not the best of summaries, sorry) (involves polyamory, no smut)

You went to the bookstore one day to buy some manga, but you got a lot more than you bargained for. You end up saving the Royal Scientist's life, and her fiancée can't thank you enough. So that's how you met the gang. But who's that skeleton guy you see in your dreams? Did the ambassador of monsters just join your swim team? Sans X Reader. Bad Words. Violence.

The biggest things in life often start with little ceremony. That's not the case for a certain skeleton in the underground, where chaos seems to breed chaos at every step. (formally titled 'Numbers')

Sans has watched as everything repeated over and over again. So has Frisk. Sans gave up a long time ago. Frisk, she still has plenty of determination. They couldn't end the loop on their own. But maybe, they could end it if they worked together? Female Frisk. Possible future Frisk/Sans.

First fanfic... When the barrier is destroyed, the last thing the Monsters expected was to be shrunk down and sold off as pets to humans and... something else. And now Frisk can't reset to fix it. The Skelebros must now adjust to being pets to a strange race among the humans. Will they survive with these strange beings? Can they undo these wrongdoings? Alternate universe.

Post true-pacifist Post Genocide: Dr. Charlotte finds herself crossing paths with a young girl named Frisk. Possible Diagnosis: split Personalities however not everything is as it seems a threat from the Underground's past rears it's ugly head and only Charlotte, Frisk and her "Friends" can stop it. But Frisk is not the only one with a strange inhuman past. (small Crossover)

The year is 2030. The monsters are now aboveground, freed by the then nine year old, now 11 year old Frisk. Papyrus is taking regular cooking lessons, Toriel's a teacher. And Sans? He's happy, finally. The nightmares have stopped, and he has an amazing wife and is an awesome dunkle to Frisk. But one day, he goes to tuck in said child, and finds a nasty surprise... SPOILER WARNING

As Judge for King Asgore Dreemurr, Sans has seen a lot of strange stuff. But when he wakes up with the feeling that something is completely wrong, he decides it's time to investigate with the only monster who could know what was happening: Royal Scientist W.D. Gaster.