Holy god, I am dead and have gone to heaven. When I first watched the BTS Prologue, when this song came on, it made me feel all of the happy feelings. Then I found a video that was just the song part and became even more happy. For a while, I slightly resented the actual version of Butterfly because "it sounded better on piano" and "didn't have the same sad feeling as before". I don't feel like that now, and I like both versions. But this... is amazing. It takes what I originally loved and extended it by almost three minutes. I encourage anyone to give this song a listen, because it is truly beautiful and shows how much hard work BTS has put into their music this past year. Enjoy.