"Cupid" is a song recorded by South Korean girl group Fifty Fifty. It was released as The Beginning: Cupid, a single album featuring a Korean version, an English version (titled the "Twin version") sung by group members Sio and Aran, and an instrumental version of the song, on February 24, 2023, through Attrakt. It is a K-pop, disco-pop, synth-pop, and bubblegum song about a young woman's unrequited love and the shame she feels because of it. The song became one of the first from a minor K-pop label to find global commercial success after a sped-up version of it went viral on TikTok. "Cupid" was Fifty Fifty's first entry on both the Billboard Hot 100 and the UK Singles Chart, making the group the fastest Korean musical act to enter either chart after their debut. "Cupid" peaked at number 17 on the Billboard Hot 100, where its 10-week-long chart run made it the longest-charting song by a K-pop girl group, and at number eight in the UK, where Fifty Fifty became the first K-pop girl group to reach the chart's top 10. The song also reached the top 10 of the charts in South Korea and Australia while peaking at number one on the Billboard Global Excl. U.S. chart and in New Zealand. A remix of the "Twin" version with Sabrina Carpenter was released on August 17, 2023. The song's original version as well as the "Twin" version and its remix, sped up version, and live studio version with all four members were included on the EP The Beginning, released on September 22, 2023. "Cupid" is written in common time in the key of D major with a tempo of 120 beats per minute, with the group's vocals ranging from a low note of G3 to a high note of E♭5. It is a "retro"-sounding K-pop, disco-pop, synth-pop, and bubblegum song that runs for about three minutes. Its lyrics describe a young woman's unrequited crush and her feeling dumb for falling in love. They were described by Sio as being about a "pure, amateur love". In the song's chorus, the group sings, "I gave a second chance to Cupid/I believed you, I'm so stupid/Let me show you, my secret love, is it real?/Cupid is so dumb," with some lyrics in Korean. The chorus for the Twin version instead uses the lyrics "I gave a second chance to Cupid/But now I'm left here feeling stupid". The group harmonizes on the song, while the latter half of the song includes a key change and a rap verse performed by Keena; the Twin version lacks the rap verse and the key change. The instrumental features synths and guitars. Molly Raycraft of The Guardian described the song as "sweet but sardonic pop reminiscent of hits by Ariana Grande and Doja Cat" with "a nostalgic sound". So Seung-geun of IZM gave "Cupid" 4.5 out of 5 stars, writing that Fifty Fifty had found their own color. Music critic Kim Yoon-ha from Yes24 noted how "Cupid" highlighted the vocals, putting them to the forefront instead of considering the voice as one of several instruments, stating that this approach reminded Kim of the Korean songs of the late 2000s rather than modern K-pop. Rolling Stone, on its mid-year list of best songs on 2023, noted the song as a "delightful in graceful simplicity, breezing by on a disco-pop groove that has the easygoing effervescence of early-2010s pop, with vocals that exude cool confidence and winning warmth, even with its busy Doja-esque rap." Billboard, when ranking the song at number ten out of fifty on a similar list, described it as "a song that seamlessly blends elements of contemporary K-pop with American girl group and bubblegum pop of the ’60s." NME included it in a similar list, calling it "relatable and endearing" for portraying the emotions and the sadness for the end of a great love "without laying them on too thick". "Cupid" was ranked at number 10 in Business Insider's list of The best K-pop songs of 2023, number 12 in Zenerate' list of The 15 Best K-pop Albums of 2023, and number 23 in Dazed's list of the Top 50 best K-pop tracks of 2023. Grammy named it one of the 15 K-pop songs that defined the year.