"Lifeline" is a song by Papa Roach which was the last song written for the Metamorphosisalbum. Frontman Jacoby Shaddix told the story of the song in a video interview: "We were packing up our equipment. I was upstairs packing up my room and I heard this riff ringing up the hallway and it was like Damn! That's sick. So we went down there and jammed it out in about an hour, got the beef to the song, tweaked it in a bunch of different ways. It's a very uplifting song. Lyrically it's about progressing as a human being, as a spiritual being in this crazy (word bleeped out). It sounds clichéd as this band is my lifeline to humanity, its what connects me to the flow of life."
The song was initially titled "Hanging On." It was changed to its present title after Shaddix decided to change the lyrics of the chorus.
The song's music video was filmed in Long Beach, California and was directed by Chris Sims (Staind, Lamb Of God, As I Lay Dying).
Jacoby Shaddix revealed to Kerrang! magazine April 18, 2009 that Clockwork Orange is his favorite film. He added that if if you start this song "at the same time as the movie, the first two minutes match up almost perfectly."