What Once was Lost

200px|right What Once was Lost is a piece included in the Halo: Original Soundtrack.

It runs for 1:42.

Appearances
It plays during the outside portion of the level 343 Guilty Spark (level) and adds to the tension the player feels before discovering the Flood. It consists primarily of swamp noises such as animal cries, with undertones to add to the suspense.

Trivia

 * The title of the piece is probably named after the Flood. And it signifies the Flood's return to the Halo universe.