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.

An accompanying music video for the song was uploaded onto SM Entertainment's YouTube channel simultaneously with the single's release.

Aespa promoted the song with televised live performances on various South Korean music programs including Show!

The members were revealed individually from October 27 to 30 (in order: Winter, Karina, Ningning, and Giselle) as well as the name Aespa, which was created by combining 'AE' which expresses 'Avatar X Experience' and 'aspect' meaning both sides.

[5] SM Entertainment founder Lee Soo-man further explained about Aespa's concept in the 2020 World Cultural Industry Forum that was held online on October 28.

[9][10] "Black Mamba" was written and composed by Omega, Ella Isaacson, Gabriela Geneva (NIIVA), Jordan Reyes, Shaun Lopez, Scott Chesak, and Yoo Young-jin while production was handled by Lee Soo-man.

[11] The song was described as an electropop and dance-pop track with a signature synth sound, a bass-heavy hook and a sweeping bridge that highlights the girls' talented vocalists.

[10] Lyrically, the song is about a being called "Black Mamba" that not only interferes with the members' connection to their avatars but also threatens their world.

Despite being a new group debut song, "Black Mamba" appeared in several publications' year-end lists, being cited as one of the best K-pop releases in 2020.

Dazed magazine ranked the song at number 33 on their list, praising its "cleverly set up what looks to be a new fantasy world story".

Fantastical, neon-lit scenes of intense, floor-dropping choreography are interspersed with moments that highlight each member exploring this new reality and engaging with the æ-members, and hinting to a villain known as the titular black mamba.

[31] Before the release of the song, a series of teaser photos and related video content promoting the quartet garnered attention for apparent similarities to the work of several artists previously shared on social media platforms.

[33] On December 22, 2020, SM released a statement stating that they have contacted the relevant artist and company that are being mentioned in regards to some scenes in the music video to explain their planning intention and on the group virtual world theme.