"Happy Death Day" is the debut single by the South Korean rock band Xdinary Heroes. The song was released by Studio J and JYP Entertainment on December 6, 2021.

Xdinary Heroes is a South Korean rock band under JYP Entertainment's sub-label, Studio J. They officially debuted on December 6, 2021, with the single "Happy Death Day". The band consists of six members: Gunil, Jungsu, Gaon, O.de, Jun Han, and Jooyeon. All of the members are involved in writing, composing, and producing the music of the band. The band's name is shortened form of "Extraordinary Heroes", meaning "anyone can become a hero".