Phenomenon is the second Japanese-language studio album of the South Korean boy group Monsta X.

The album included two previously released Japanese versions of the Korean title tracks "Alligator" and "Shoot Out".

[1] The title track "X-Phenomenon" was pre-released on July 15, 2019 ahead of the album's full release.

[2] Chris Gillett of SCMP wrote that Phenomenon, with the exception of the Japanese versions of "Alligator" and "Shoot Out", presented "a different sound from their previous album Take.2 We Are Here", with "a less of the EDM focused style" and "a more aggressive tone".

[3] "Livin' It Up" and the Japanese versions of "Alligator" and "Shoot Out" were all certified gold singles by RIAJ.