In August 2017, JYP Entertainment (JYP) officially announced the agency's new reality survival show to launch a male idol debut project. More details and teasers were released in the next two months, including the show's title—Stray Kids. Prior to its premiere, JYPE released Stray Kids' first music video for a song titled "Hellevator", which was later released as a digital single. The show premiered on October 17 and though there were eliminations. The first who was eliminated was Lee Know and the second was Felix, but it ended with all nine members as the final line-up of the group.
Along with the launch of Stray Kids' official website, JYP announced the release of the group's pre-debut extended play (EP) titled Mixtape. It contains seven tracks co-written and co-composed by the members, including "Hellevator" and other songs that they performed during the show. The EP, along with the performance video of its second track titled "Beware", was released on January 8, 2018, while the performance video of "Spread My Wings" was uploaded online a week later. It debuted at number 2 on Gaon's Album Chart and Billboard's World Albums chart.
