Bubble Pop!

Release and reception

On June 30, 2011, the first single, "A Bitter Day", was released digitally. It featured guest singer G.NA in the chorus and rapping by Yong Jun-hyung of Beast. It was co-written by Yong and Choi Kyu-sung. The song peaked at number 10 on the Gaon Weekly Digital Chart and at number 165 on the Gaon Year-End Digital Chart for 2011.

On July 5, 2011, the EP's title track, "Bubble Pop!", and its music video were released. The music video features a cameo by MBLAQ's Lee Joon. The Music Video was filmed on Okinawa, Japan Hyuna promoted the song on music shows from July 8, 2011 on KBS's Music Bank, MBC's Show! Music Core, SBS's Inkigayo and Mnet's M! Countdown. The song reached number 4 on the Gaon Weekly Digital Chart and finished 2011 at number 21 on Gaon's year-end chart. It has sold a total of 2,694,310 digital copies.

In December 9, 2011, title track "Bubble Pop!" ranked #9 on American music magazine SPIN's "20 Best Songs of 2011" list.

The song was parodied in the 2016 Family Guy episode "Candy, Quahog Marshmallow!".

Promotion and controversy

Hyuna promoted the title track "Bubble Pop!" on music shows in July 2011 on KBS's Music Bank, MBC's Show! Music Core, SBS's Inkigayo and Mnet's M! Countdown. The EP's introduction song "Attention" was also used in the performances.

In August, Cube Entertainment halted promotions because the title track's video, choreography, and on-stage costumes were deemed by the Korea Communications Commission (KCC) to be "too sexually suggestive". Cube Entertainment decided to promote a follow-up single "Just Follow", featuring rapper Dok2. Hyuna's performance on the Inkigayo music show featured rapper Zico from the boy band Block B instead, and featured lyrics he re-wrote.