Underfell but everytime frisk dies, the world resets and more flowers grow on her (yes, this one is a girl). Sans is aware of resets but no one else is, and thus grows softer.
Hey fanon undertale fans! Frans is pedophelia. “ITS AN AU!!!!”; “YOU NEED TO RESPECT US!!!!!!11!!1!”; “FRISK IS 20 IN MY AU!1!1!1!!1!1!1!1”; “IM REPORTING YOU1!1!1!1!1!”