Originally featured in the 1993 animated movie "The Nightmare Before Christmas," the a cappella group Pentatonix completely re-envisioned this crazy, spooky Christmas song, bringing it new life and awareness. Built on the notes from the ancient Dies irae chant, this song has musical shifts and clever changes of direction that make it a unique experience for the holidays. Perform a cappella, or use the optional piano or instrumental accompaniment for extra support.