In 2021, Stray Kids competed the competition show
Kingdom: Legendary War. In the second part of the third round, the group performed the
mashup of their song "
God's Menu" and
Blackpink's "
Ddu-Du Ddu-Du" with the theme heavily inspired by the film
Deadpool (2016). They used various properties inspired by the film such as
Deadpool's mask and
Ant-Man's tanks. This performance was noticed by
Deadpool actor
Ryan Reynolds, who mentioned them in a fan edit video of
Deadpool and the show on
Twitter and following their social media accounts, then
Wolverine actor
Hugh Jackman also noticed and followed. Reynolds sent his signed
Aviation American Gin along with Deadpool mask to Stray Kids, and the group's
Bang Chan sent Reynolds the signed
In Life (2020) album back. During the promotion of
Free Guy (2021), Reynolds did a video interview with Bang Chan and expressed their thankful feelings to each other. During
Deadpool & Wolverine press conference in
Seoul, South Korea, Reynolds mentioned his interest in K-pop by mentioning Stray Kids. After the press conference, Reynolds and Jackman were reported to have a private meeting with Stray Kids' Bang Chan,
Felix, and
Han, and prepared a special content for the film. On July 17, 2024, the track list for the
Deadpool & Wolverine soundtrack was revealed, which features "Slash" by Stray Kids as the fourth track. The song was released as a
promotional single ahead of the soundtrack album on July 23, 2024. == Composition ==