Here are some reasons “Black Mamba” by Aespa is popular:
Aespa came from one of the Big Three: SM Entertainment. We can’t just deny the privilege of debuting from a well-known company. Since they did, many people have anticipated their debut.
People were curious and interested about the virtual members. It is quite a unique concept for a k-pop group to have AI avatars, so this just meant that they were the talk of the town when they first debuted.
Their debut was hinted from a music video of SuperM. Fans saw a spoiler at the end of the music video, One (Monster & Infinity), and this just added spark to their interest and curiosity. + All groups under SM Entertainment are interconnected and are all in one universe called “SM Culture Universe”