Skelebros

Skelebros is the familyship between Sans and Papyrus from the Undertale fandom.

Undertale
Sans and Papyrus are brothers and are the one of the major characters you meet in Undertale. They have been shown to love each other more than seemingly anything, as they appear to have no other family or relatives. Details of their past are unknown, but is known that they suddenly “showed up” to Snowdin one day. The two live together in a house in Snowdin Town.

Most of the dialogue between Sans and Papyrus mentions each other. They often compliment each other, while Papyrus still gets angry at Sans for being a “lazybones” and shirking his work duties. Papyrus also gets cross whenever Sans repeatedly tells puns.

Sans seems to think very highly of his “cool” brother, scolding the player when they choose to call Papyrus “not cool” instead of cool. And then, sans will call papyrus "a real star".

When Frisk first met Sans, Sans raised the issue of Papyrus' recent low mood with Frisk, hoping that Frisk could help him make Papyrus' day.

In the area of the word search game, if Frisk chooses that junior jumble is more difficult, Sans will thank Frisk for taking into account his brother's feelings after Papyrus leaves.

In the following area, Papyrus mentioned Sans to Frisk, "SOMETIMES I WONDER WHAT HE WOULD DO... WITHOUT SUCH A COOL GUY TAKING CARE OF HIM???".

Beside their TV, Sans and Papyrus chatted a series of notes about picking up socks.

When Frisk investigates Papyrus' computer, Papyrus will tell Frisk"A JEALOUS TROLL HAS BESIEGED MY ONLINE PERSONA. ALWAYS SENDING ME BAD PUNS IN A GOOFY FONT". It's highly likely done by Sans.

There are many action figures on the table next to Papyrus' bed, and he said they were given to him by Santa. However, there is a thank-you letter written to Santa next to Sans' cabinet, which confirms that Sans played Santa and gave Papyrus action figures.

Deltarune
Sans lives in Kris’s hometown with his younger brother, which can assumed to be Papyrus. When Kris talks to Sans, he asks them to meet his brother.

Family
Sans and Papyrus are a popular duo in the Undertale series, and there are countless fan-works focusing on their brotherly relationship. Sans is often seen as the protective older brother while Papyrus is the more innocent younger brother.

On AO3, the non-romantic ship between Papyrus and Sans is the fourth most popular ship for both characters and the seventh most popular ship in the fandom. It is also the only non-romantic ship in the top 10 most written Undertale ships.

The term Babybones refers to fanworks focusing on Sans and Papyrus as young children. This often involves Papyrus as a baby and Sans as an older brother. Occasionally, Sans is a baby as well. Sometimes W. D. Gaster appears as their father.

Romantic
Some people like to ship Sans and Papyrus romantically, possibly because the shippers think they have sexual love for each other, despite it being brotherly love. Others hate the pairing due to it being incest. Sometimes, the pairing is in an AU where Sans and Papyrus are not related.

On AO3, Sans/Papyrus is the most popular ship for Papyrus, the second most popular ship for Sans and the third most popular ship in the fandom.

Sometimes different AU versions of Sans and Papyrus are shipped. Some of the AU versions of Fontcest have unique names, with “Classic Fontcest” referring to the main versions.

Fandom
FAN FICTION
 * Sans/Papyrus tag on FanFiction.net
 * Sans/Papyrus tag on FanFiction.net
 * Sans/Papyrus tag on FanFiction.net
 * Sans/Papyrus tag on FanFiction.net

DEVIANTART

TUMBLR

Trivia

 * Sans and Papyrus are the only two skeletons featured in the game; Gaster’s species remains unconfirmed.
 * This has lead some to believe that they are the last two skeletons in the underground.
 * This also leads some fans to believe that the mysterious identity of Gaster, whose species is unidentifiable from his sprite and canonical artwork alone, could also be a skeleton. Consequently, also related to the two.
 * Sans and Papyrus both use blue magic.
 * It is only after the release of Deltarune that it is confirmed that Papyrus is the younger brother to Sans.