Underswap Sans, ULCFan Wiki

Underswap is an AU where many of the characters' roles are swapped, as well as their personalities, though some quirks tend to stick in places, or are modified. Sans is the excitable, confident, extremely optimistic human hunter, while Papyrus is the laid back, protective bro following Chara

UNDERSWAP - Sans by Bloody-Uragiri on DeviantArt

Underswap and Fellswap - Sans and Frisk by WolfKIce on DeviantArt

Underswap Sans (Canon), Wiki

Underswap Sans, Wiki

Team Switched Underswap Sans by Flybydogey101 on DeviantArt

Underswap Conviction Sans all phase by AYGoftenover on DeviantArt

Underswap Sans (Canon), Wiki

Underswap Sans Reference by CyberFell on DeviantArt

Underswap - Belief sans by Pixelbit0 on DeviantArt

Sans, TS!Underswap Wiki

Team Switched Papyrus, ULCFan Wiki