"Rotten to the Core" is a song from Disney Channel's 2015 television film Descendants, whose music and lyrics were composed by Joacim Persson, Shelly Peiken and Johann Alkenas. The song was performed in its original show-tune version in the film by the main cast – Dove Cameron, Booboo Stewart, Sofia Carson and Cameron Boyce – in their vocal roles as Mal (daughter of Maleficent), Carlos (son of Cruella de Vil), Jay (son of Jafar) and Evie (daughter of The Evil Queen). The song peaked at number 38 in the Billboard Hot 100. A second version, performed by actress and singer Sofia Carson, was released as a single on December 18, 2015.

A midtempo dance-pop song, "Rotten to the Core" exhibits elements of pop, dubstep and hip hop. Built on a beat, multi-tracked harmonies, the song's instrumentation includes slow-bouncing synthesizer tones and keyboard. The song was written by Joacim Persson, Shelly Peiken and Johann Alkenas and produced by the duo Twin. Cameron's vocals span from the low note of F₃ and Carson vocals span from the high notes of F₅. The song introducing the four villainous offspring in the film. Gary Wright of Rotoscopes noted that part of the song is spoken, whispered, reflecting an ominous tone to the voices, while only the chorus is sung. Lyrically, the song talks about the feelings of the villains, who are evil and wicked, but they like to be just like this ("Who's the baddest of them all? / Welcome to my wicked world, wicked world"). The stanzas are sung also among the four artists, while the pre-chorus is only performed by Cameron and the chorus by Booboo Stewart.

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