(Original sans template by dcdragon) Underfell Sans looks very similar to his Undertale counterpart. He is a skeleton with sharp teeth, with one being gold. His right eye is seen to be glowing red 24/7. He wears a black winter jacket with a jacket fur flame hood and a gray cotton hoodie, and a red sweater with a golden chain with black pants that have yellow stripes going down. He wears red shoes with yellow socks. Sans wears a black jacket, with the "fluff" at the collar being notably more ruffled than the original Sans'. His shirt is a red color in contrast to the normal white shirt. His shorts have a yellow strip instead of a white one and he wears black/red/white shoes or red slippers, as opposed to his counterpart's light blue slippers. His body structure appears the same as his counterpart (besides his teeth).

More facts here: https://underfell.fandom.com/wiki/Sans