Side by side, we march as one. Humans and Elites will die. The Earth will fall if we strike together. So forth shall all of life.
Dread Intrusion is a piece included in the Halo 3: Original Soundtrack. It plays during the level Floodgate, and includes the tracks Dread Intrusion, Black Tide, and Old Friend.
The middle part of the piece (Black Tide) is a remixed version of the song Ghosts of Reach from the Halo 2: Original Soundtrack.
It runs for approximately 5 minutes and 25 seconds.
At around 0:50, a reversed message can be heard.
The voice sounds and echoes similar to the Gravemind.
List of music heard in the Halo series