Commercially, the single reached the charts in five countries, peaking at number 49 in South Korea and number 5 on the US Billboard World Digital Songs. The song's music video achieved the highest number of views for a K-pop group's debut video, with 21.4 million views in 24 hours. An accompanying music video for the song was uploaded onto SM Entertainment's YouTube channel simultaneously with the single's release. The lyrics are about a being called 'Black Mamba' that not only interferes with the members' and avatar's connection, but also threatens their world and as such is abhorred by the members.

Musically, 'Black Mamba' was described as a pop, electropop and dance-pop track with a signature synth and EDM sound and bass that is paired with an addictive hook. The song was written and composed by Yoo Young-jin, while also composed by Omega, Ella Isaacson, Gabriela Geneva (NIIVA), Jordan Reyes, Shaun Lopez and Scott Chesak. Originally released as a standalone single on November 17, 2020, by SM Entertainment, the song was later included on the group's second extended play Girls, which was released on July 8, 2022.