"Butterfly Effect" (バタフライエフェクト) is a single by Japanese rock band Sid, released on May 10, 2017, by Ki/oon Music.
On April 6, the band's new visual was revealed in promotion of the single and they announced the dates that the song would be available digitally.
However, a special iTunes digital version was also released containing three bonus tracks: "Mousou Nikki 2", "V.I.P" and "One way", old songs of the group.
[2][3][4] The music video for "Butterfly Effect", starring dancer Aoi Yamada, is themed around "infection."
It shows a high school girl gradually becoming infected as she listens to the song while walking through the streets of Shibuya, Tokyo.