"Megalo Strike Back" is a song composed by Toby Fox. It was released as the 20th track on the collaborative album I Miss You - EarthBound 2012, an album made as a celebration of music from the MOTHER series. The album itself contains 22 tracks related to the second game from the series, EarthBound, with "Megalo Strike Back" meant to be interpreted as "a rockin' midi boss battle theme for an alien overlord", according to Toby Fox on his now-defunct website.[1]
However, after the release of Undertale, a game also made by Toby Fox, "Megalo Strike Back" quickly became popularly associated with Chara, with many fans labelling it as their supposed boss battle theme. Some fans have also compared the song to "Megalovania", another song by Toby Fox, with the implication that "Megalo Strike Back" is a sequel to "Megalovania". Neither of these theories have been confirmed by Toby Fox.
Many remixes and arrangements of "Megalo Strike Back" have been made over the years, and it is frequently used in fan-made Chara boss battles, with a popular example being the Chara Boss Battle animation made for Dreemurr Reborn, an Undertale AU. Additionally, the song was remixed for the Friday Night Funkin' mod, V.S. Chara, as well as the joke Pikmin 2 mod, 🅱️ikmin 269.
The first rip to feature "Megalo Strike Back" was "Stage Select (Doc Robot Version) - Mega Man 3" on January 4, 2017, where it was featured at 0:57. Most rips featuring the song are melody changes or arrangements, with some rips referencing the theories surrounding the track's supposed connection to "Megalovania" (via pairing of the 2 songs) or Chara.