On the 23rd of, at 6 PM(KST) , Billllie released their debut single album "Side-B: Memoirs of Echo Unseen" through various music streaming platforms.

The title track of Billllie is 'DANG! (hocus pocus)'. This song delves into the inner self, constantly communicating until a moment arrives when everything familiar loses its essence, and the boundaries of the 'self' expand. It's characterized by its dynamic beats and staging, all while Billlie artfully conveys the gap between the way they perceive themselves and how others perceive them, using their unique and artistic language.