"Robert Rodriguez: Mickey [Rourke] had this one piece of music he would play on the set to get him into the character of Marv. We couldn't use it in the movie because it was too expensive. It was a Johnny Cash song - it was actually a remake of a Nine Inch Nails song called Hurt. You play that song and if you listen to that song that's how he did Marv for all the voiceover. It would just help him to get into that place - that Marv place. We got some remarkable work from him just from playing that song. That's his time machine. His transport."