His New Favorite Color

Reader, Frisk (Undertale), Sans (Undertale)/Reader, Sans (Undertale), Papyrus (Undertale), Undyne (Undertale), Alphys (Undertale), OCs, Toriel (Undertale), Mettaton (Undertale), Sans/Reader, Catty (Undertale), Bratty (Undertale), Alphys & Undyne, Mettaton/Papyrus, Sans (Undertale)/Original Female Character(s), Sans (Undertale)/You, Probably everyone eventually

Fluff Eventual Smut Reader-Insert Female Reader Bad Puns SO MUCH FLUFF Reader Is Not Frisk Mute Frisk gender neutral frisk Post-Pacifist Route We're All Sinners Frisk Uses Sign Language more characters later - Freeform im tagging at 1am Some OCs because of course