"Catchy Song" is a song by American DJ and producer Dillon Francis, featuring guest vocals from rappers T-Pain and Alaya High (the latter credited on the soundtrack release as her stage name That Girl Lay Lay).
The song became the main theme to the 2019 Warner Bros. Pictures film The Lego Movie 2: The Second Part, as it is written by Jon Lajoie, and produced by Francis.
The first use of the song in The Lego Movie 2: The Second Part is in a scene in which most of the film's characters are subjected to the song and all except Lucy dance to it, while simultaneously the denizens of Harmony Town sing it to Emmet and Rex.
The song is briefly sampled in the unhappy reprise of "Everything Is Awesome" ("Everything's Not Awesome") when Lucy proclaims that the song is "gonna get stuck inside your heart", a proclamation made to bring back the hope of defeating Rex and restoring harmony.
[citation needed] The song also plays in its entirety during the first third of the end crawl during the closing credits.