From Halopedia, the Halo wiki
This article is about the soundtrack. For Covenant vehicle, see Shadow.
Shadows is the twenty-fourth piece included in the Halo: Original Soundtrack.
It is notably the shortest piece in the Halo: Original Soundtrack. The piece begins with high strings, followed by siren sound effects (like those heard in Truth and Reconciliation Suite), with percussion fading in, and finally joined by electric guitar. In-game, only the siren sounds were used.
The soundtrack can be heard:
The siren sound effect would become associated with the Flood throughout the series, and used again in the following tracks: