Megalovania is the boss theme for Sans, the final opponent in Toby Fox's 2015 role-playing game Undertale, and it became one of the game's most famous tracks. Its rapid melody and relentless pace matched a battle known for its difficulty, and players shared clips, covers and remixes long after finishing the game. As Undertale grew into a wider internet phenomenon, the theme turned into shorthand for an intense confrontation, which is why very short cuts remain popular in memes, gaming videos and reaction edits today.