"Copycat" was released on July 14, 2017, as the fourth single on Eilish's debut EP Don't Smile at Me. "Copycat" was written by the singer and Finneas O'Connell, her brother and the track's sole producer. Mastering and mixing was handled by the studio personnel, John Greenham, and Rob Kinelski, respectively. A remix by Sofi Tukker was released on January 12, 2018. In an interview with Genius, Eilish mentioned that she wrote the song with her brother about a girl who copies everything that she does. "I write with my brother mostly. That song, we were just in his room, and I was like, 'Yo! There's this fucking girl and she keeps doing everything that I do. And I want to write about it.' Because it was in my mind."
Composition and lyrical interpretation
"Copycat" has been described as a hip-hop-influenced electronica and pop track in press reviews. According to sheet music published at Musicnotes.com, "Copycat" has a slow and constant tempo of 64 beats per minute and is played in the key of E minor. Eilish's vocals span a range of E3 to G5. It features a minimalist production consisting of a bass guitar and piano. Titiana Crisano of Billboard compared the instrumetation to the later work of XXXTentacion and Tyler, the Creator. In an interview with Billboard, Eilish stated that Finneas came up with the "weird, creepy bass sound" and she thought it was cool. The song is Eilish's response to someone who kept copying everything she is doing: "Copycat trying to cop my manner/Watch your back when you can’t watch mine/Copycat trying to cop my glamour/Why so sad, bunny, you can’t have mine?" As the song reaches the bridge, the instrumentation turns into a piano ballad and Eilish's vocals become somewhat quiet and build into a falsetto and apologizes as she warns the person that they have reached their limit: "You just crossed the line/You've run out of time/I'm so sorry, now you know/Sorry I'm the one that told you so." She then tricks the listener with "psyche" and returns to the original dark lyrics.
Reception
Insider Libby Torres, called the track a "precursor of sorts to 'Bad Guy'" and felt that "Copycat" lacks the "driving bass and increasingly-layered vocals" that made "Bad Guy" a good song. However, Torres concedes it is still a "worthy song that provides a tantalizing glimpse of Eilish's early potential". NME Thomas Smith commented that "Copycat" was "impossibly swagger" with "scattered beats and energetic live performances making it a welcome entry point for many fans." Niall Byrne of The Irish Times described the ending as a "menacing synth" that reappears to "underscore her sullen demeanour". Kirsten Spruch of Billboard described the track as a "ground-shaking opener". Commercially, "Copycat" did not enter the BillboardHot 100, however, it peaked at number 12 on the Bubbling Under Hot 100 chart. The song also peaked at number 100 on the Canadian Hot 100. "Copycat" has been awarded notably a double platinum certification award from the Mexican Association of Producers of Phonograms and Videograms, A.C..
