This is a re-recorded version of a previously unfinished song from the World Painted Blood sessions written by the band's late guitarist Jeff Hanneman. Slayer guitarist Kerry King told the Artisan News Service about the track: "'Piano Wire' was done on the last album, World Painted Blood. [It was] probably the last song we worked on, and that's why it didn't go on the record. It was an afterthought."
"Tom [Araya, vocals] didn't… He didn't put a good performance on it, and it was just kind of left like that. I was intending to use it, but it needed some pizzazz. It was completely done other than that."
"That's my lead on it from six years ago. So we had Paul [Bostaph, drums] redo the drums on it, and Tom got comfortable with the lyrics and just went in and gave it the take it needed to be finished. And it fits in with these songs great, I think."