IU’s digital single “삐삐 (BBIBBI)” celebrates the singer’s 10th anniversary since her debut.
With a playful, shifting percussions and a soft blend of harmonies, the track is IU’s first song that falls in the alternative R&B genre.

“BBIBBI” is the phonetic sound a bell makes in warning of something crossing some sort of boundary. The lyrics of the song express a pleasant, cheerful message to those who cross the line in personal relationships. In a society where people have little regard for the personal bubble of others, IU writes about the need for respect and privacy in modern society.

On Cafe Daum IU further explains the song:

The song conveys the message of throwing a cheerful and simple warning at those who have crossed the line. More important nowadays than ever, is to not restrict or decide for others based on one’s own standards, but for equal and independent individuals to have healthy ties. The song tells the story of people living in the modern age.

Billboard published an article following the song’s release, saying:

IU is seen emulating a variety of different roles, such as languishing around in high-fashion or dancing around in retro looks, and throwing away newspapers and looking out from a window with binoculars while wearing a Gracy Kelly-style scarf as if she’s peering out for paparazzi. As she sings about not caring about others and saying that it’s “not my business,” she coyly stares down the camera and shows off the different sides to herself.