"Dark Horse" combines the genres of trap, hip hop, pop-rap and electropop, replicating what has been described as a "Southern rap-techno mashup".

Perry, in interviews, said she wanted the song to have a "witchy, spell-y kind of black magic-y idea", so she wrote it from the perspective of a witch warning a man not to fall in love with her because if he does, she will be his last.

The song was part of a competition sponsored by Pepsi in which fans could vote via Twitter on whether they would prefer either "Dark Horse" or "Walking on Air" to be released as the first promotional single from Prism.

It also reached the top ten in almost 20 countries, including New Zealand, the United Kingdom, Sweden, and Venezuela, as well as on the Digital Songs chart of Billboard magazine.

[4] In 2014, Flame, a Christian rap artist, filed a copyright infringement lawsuit against Perry and the other songwriters, claiming that "Dark Horse" copied from his 2008 song "Joyful Noise".

However, in part due to a similar judgment that found Led Zeppelin's "Stairway to Heaven" clear of copyright infringement in the Ninth Circuit, the jury award was vacated on appeal in March 2020.

[6] Perry described the song as a "juxtaposition", as it mixed her, a pop music artist, with an "urban kind of hip-hop-flavored background soundtrack"; and its lyrics as "witchy and dark", written from the perspective of "a witch warning [a] man to not fall in love with [her]", and if so, she would be his last.

Perry then asked producer Dr. Luke to contact one of his Kemosabe Records artists, American rapper Juicy J, for a guest verse.

[8] In a press release on August 20, 2013, Pepsi announced a partnership with Perry to promote her fourth studio album Prism: a social "tweet-to-unlock" voting program, encouraging fans to tweet the hashtag #KATYNOW in exchange for song titles and lyrics.

[20] Musically, the verses are built around icy rhythms and chopped and screwed vocal samples, while the chorus' feature Perry singing into a gradual crescendo.

[23] A writer for the Winnipeg Free Press described the song as "brooding, borderline sleazy trap-pop excursion that comes across like a stripped-down version of 'E.T.'

[24] Marc Hogan from Spin called the lyrics a "cliché salad" but believed that the song had potential to become a hit due to its "soaring hooks" and "sleekly sculpted production".

[26] Digital Spy's Robert Copsey questioned the decision to not have a proper chorus in "Dark Horse" and the inclusion of Juicy J, though he praised the "sleazy" beat and "sultry" vocals from Katy Perry.

[28] Keith Murphy from Vibe called the track "infectiously sexy",[29] while John Walker from MTV was similarly positive about the song, though he wrote that Juicy's verse was "phoned-in".

[35] Writing for ABC News, Mesfin Fekadu commented that "her team fare[d] better" in the song and observed that the "Southern hip-hop and electronic flavors" present on it were factors that made it "work".

[46] As of August 2020, the song has sold 6.4 million copies in the nation,[47] and has been certified eleven-times platinum by the Recording Industry Association of America (RIAA).

[49] "Dark Horse" peaked at number two on the New Zealand Singles Chart becoming Perry's twelfth top ten, and was certified double platinum by the RMNZ.

"Dark Horse" sold 13.2 million units worldwide in 2014, finishing as the second best-selling song of the year according to the International Federation of the Phonographic Industry (IFPI).

The video transitions to a different scene where Pätra, now wearing a longer dress and a black wig, sits in an extravagant Sphinx-like throne while pharaohs gather to bring her expensive gifts (such as a large diamond) in an attempt to "win her heart".

After retrieving the first suitor's gift, she hits the man with a magical bolt of lightning from her hand, turning him into a pile of sand, and takes his jewels to wear on her teeth as a grill.

At the top of the pyramid, Pätra, dressed as Isis, uses her powers to conjure up a magical "perfect storm" with pink, purple, and violet clouds.

Cullen, the director, defended the music video, saying that, while he believes it is dangerous to rip things directly from present cultures without adding anything to them, Ancient Egypt is part of what he calls our "shared collective mythology".

Egyptologist David P. Silverman praised the music video's use of Egyptian imagery and the interest it could generate to viewers: "[Egypt has] always been a part of popular culture.

[67][68] Cho'zyn Boy, a DJ for Flame in 2014, stated that Perry's song is "identical" to "Joyful Noise", but ten BPM slower in tempo and one step higher in pitch.

[72] In August 2018, Christina A. Snyder from the United States District Court for the Central District of California ruled against a summary judgment, arguing that the plaintiffs "demonstrated a triable issue of fact as to access because 'Joyful Noise' achieved critical success, including a Grammy nomination, and was readily available and viewed millions of times on YouTube and MySpace.

"[68] Another argument from Perry and the other defendants was that because Ojukwu never registered the beat he produced and later licensed it to Flame, "Joyful Noise" was itself a derivative work.

"[67][76] On July 29, 2019, a federal jury found that Perry, Juicy J, Dr. Luke, Max Martin, Cirkut, and Sarah Hudson were guilty of infringement, along with Capitol Records, Warner Bros. Music Publishing, Kobalt Publishing, and Kasz Money Inc.[67][68] The jury awarded the plaintiffs $2.78 million, of which Perry herself was ordered to pay $550,000.

[78] While the motion was under consideration, in early March 2020, the Ninth Circuit (of which the Central District of California is a part of) issued a ruling in a similar long-running lawsuit on whether Led Zeppelin's "Stairway to Heaven" violated the copyright of the song "Taurus" from the band Spirit.

The "dark and mysterious" performance featured a "haunted forest" design with animatronic horses, broomstick pole dances, and a controlled fire.

[89] On February 1, 2015, the song was performed by Perry during the Super Bowl XLIX halftime show, where she was on a chessboard, with her dancers as chess pieces.