Sans is a major character in the indie game Undertale. More information about the character here: https://undertale.fandom.com/wiki/Sans

In the Undertale mod, Sans is a somewhat neutral mob. Just like in Undertale, Sans has very low health and most weapons would one shot him. When defeated, he can drop bones, blue souls, Gaster Blasters, and Blaster Ammo. A Boss Sans will spawn in the dead Sans place, who will actively attack the player.

Mod link (Slightly outdated): https://www.curseforge.com/minecraft/mc-mods/undertale-mod