 "Butter-Fly" was performed as the ending theme song to the 1999 film "Digimon Adventure" and later became the opening theme song to the television series of the same name.It was the first time Wada had sang a rock song, as he originally performed "Butter-Fly" as a ballad.Originally released on April 23, 1999, the single was re-released on August 1, 2004 with new CD artwork to commemorate "Digimon Adventure's" 5th anniversary.