Megalovania is best known as the intense battle theme for Sans in Undertale, released in 2015 and composed by Toby Fox. The melody had earlier appeared in his EarthBound Halloween Hack, but its Undertale boss fight made it a global gaming anthem. Clips, remixes and edits spread across YouTube and TikTok, where creators paired it with showdowns, speedruns and ironic everyday battles. The second version circulating online keeps that same recognisable lead while giving editors a fresh cut for montages, so it remains a shorthand for a high-stakes confrontation.