Dark Horse’s video created fuss with its Egyptian-themed symbolism, with many believing them to be direct Illuminati references. Katy Perry admitted to Rolling Stone to not knowing what Illuminati is, further criticizing the internet-generated rumors: “Weird people on the Internet that have nothing to do find, like, strange triangles in your hand motions”.
But the song itself was just as eccentric of a move for Katy Perry, switching from her usual over-the-top style to a more minimalist and electronic style. Vibe viewed Dark Horse as the “antithesis of the singer-songwriter’s usual hopeful material”, characterizing it as “dark and sleazy without the morning after guilt”. Both Billboard and Winnipeg Free Press noted the trap influences, the former feeling that “the pop singer sashays toward trap music” and the latter describing the song as a “brooding, borderline sleazy trap-pop excursion”. Slant Magazine felt more genres were incorporated into Dark Horse, calling it an “inventive trap/grime/EDM mash-up”.
Famous Southern rapper Juicy J is featured in the song’s intro and rapped bridge, being the only guest star on the entire album. Reviews of his contributions were mixed. Digital Spy felt they were unnecessary, while Consequence of Sound viewed it as a mere token. On the other hand, Billboard praised the rapper’s “usual rapid-fire flow” and Vibe even felt it signaled his “hip-hop comeback”.
Dark Horse spent 4 consecutive weeks at number one in Billboard Top 100 before being dethroned by Pharrell Williams’ Happy.