[1] Due to the various girl groups that debuted and succeeded in 2009 with a cute concept, Brown Eyed Girls felt that having a cute and innocent concept would work against them.

The song was released to various digital outlets in July 2009, after which it quickly topped various online charts.

By the end of 2009 the song was downloaded 3,095,468 times becoming one of the best-selling singles in that year.

Later on, the group revealed a repackaged version of the album titled Sign that included a new single, "Sign", along with "Drunk On Sleep" and a remix of their previous hit "Abracadabra".

It featured scenes of violence and death, including Ga-In drowning in a tank of water.