Dread Intrusion

200px|right Dread Intrusion is a piece included in the Halo 3: Original Soundtrack. It plays during the level Floodgate.

Note: Around the start/middle of the piece, it plays a remixed version of the song Ghosts of Reach. The version from Ghosts of Reach is heard around the 1:10 mark.

It runs for 5 minutes and 25 seconds.

At around 0:50, a reversed message can be heard. The voice sounds and echoes similar to the Gravemind.