Although its high energy, drums and forceful vocal performances recall the group's early sound, it is absent of their typical folk stylings.

[5][6][7] They also performed the song on Night Two of KROQ's Absolut Almost Acoustic Christmas 2019, alongside "Mountain Sound", "Wars", and "Little Talks"; and Triple J's Like a Version where they also played a cover of Post Malone's "Circles".

[24][21] Sophia Simon-Bishall of The Line of Best Fit enjoyed it as "startling and thrilling", but also claimed it promised a diverse sound that the rest of the track list failed to live up to.

[25] DIY's Louisa Dixon and Slant Magazine's Graham Kervin were disappointed most of Fever Dream followed a forgettable pop style instead of the "arena-ready punchiness" and powerful vocals of "Alligator".

[21][17] Paste's Andy Crump enjoyed "Alligator" as a "banger" and lamenting that "if, from start to finish, the whole record worked half as well as 'Alligator,' it’d be a bold new chapter in Of Monsters and Men's narrative".

He argued that it is "catchy and iridescent enough to appeal in a commercial sense", but was absent of "almost all of what makes Of Monsters and Men exceptional in the first place", finding it similar to "countless generic empowerment anthems residing within modern pop music".

[26][27] On the Billboard issue dated 13 July 2019, "Alligator" was at number four on the magazine's Rock Airplay chart, garnering 6.7 million listens according to Nielsen Music.

[30] In the issue dated 24 August 2019, "Alligator" became the band's first Rock Airplay chart topper, launching from 4–1 as a result of to its 8.8 million impressions, 9% higher than that of the previous week.