Talk:Sans/@comment-27987960-20160316035658/@comment-25824232-20160316050800

That's one of two AUs: Underswap, a role swap AU; Sans and Papryus switch places.

And then there's the Sole Survivor Papyrus AU where Sans is killed instead of Papyrus.

Both are fan-made, and never appear in the games.

Although, they are interesting concepts.