SM Entertainment stunned the K-Pop world with this surprise MV teaser for SNSD's new song, "Bad Girl"! "Bad Girl" was originally included in SNSD's first Japanese album, "Girls' Generation". The girls have been performing the song during their recent concerts and on some Japanese music programs, but this is the first confirmed sign that they'll be promoting this song next. Check out the MV teaser below, and stay tuned to allkpop for more details!