From Halopedia, the Halo wiki
Incubus is an American alternative rock band. They are from the Fernando Valley of southern California. For the Halo 2 soundtrack, they created four songs that are featured on the Halo 2 Soundtrack (Volume 1). The songs are collectively known as "The Odyssey". The original was called "Follow (1st Movement of The Odyssey)". There are also three more movements of the song: 2nd Movement of the Odyssey, 3rd Movement of the Odyssey, and 4th Movement of the Odyssey. As the songs numerical value for "Movement of the Odyssey" goes up, they get longer (with one exception). The track "Follow (1st Movement of the Odyssey)" was the only track to appear in game. It is played during the final few minutes of gameplay in the Halo 2 level The Arbiter.