Board Thread:General Discussion/@comment-26680716-20160501054031/@comment-33343984-20180227235101

I believe it is Chara's or Frisk's theme. Becuase notice how Sans fights you and not the other way around, meaning that your song should be the one playing. There have been some files in the game, which have been found and named as "The Song That Might Play When Battling Sans" Which I believe is San's actual theme.

Also, notice that the term "Megalovania" or "Megalomaniac" means that someone is obsessed with their own power, but San's personality is nothing like that, on the other hand, Geno-Frisk and Chara are absolutely obsessed with power, as they kill everyone, leading me to believe Megalovania is their theme (Chara and Geno-Frisk)