Sans canonically does the fortnite dance

nothing useful. — sans' (lack of) motivation: his refusal to stop

Boss Guide - Undertale Guide - IGN

Steam Workshop::undertale.fandom.com/wiki/Sans/In_Battle

My first time choosing that dialogue option, and I was treated to an incredibly wholesome scene : r/Undertale

Yes, but sans do yourself a favor and take your own advise.

Sans' Boss Fight - Genocide Route (Undertale) - Dialogue Script

nothing useful. — I'm a huge fan of your theories. Yesterday I saw a

UF! Sans Dialogue Box by NimaSakibo on DeviantArt

What happen's if you keep retrying in Sans' boss fight? : r/Undertale

Genocide Route, Undertale Wiki