Megalovania is the iconic boss battle theme associated with Sans the Skeleton in Toby Fox's hit indie game, Undertale. While the track originally appeared in a Mother 2 ROM hack and Homestuck, it gained legendary status through Undertale’s Genocide Route boss fight, known for its extreme difficulty. The meme typically revolves around the first four notes of the song, which are used as a punchline for unexpected misfortune or as a warning that someone is about to face severe consequences. In meme culture, it often features Sans’s glowing blue eye and the catchphrase 'You're gonna have a bad time,' serving as a universal symbol for impending doom or ironic intensity.