Rat's Nest

Rat's Nest is the name of a map that was announced in the Bungie Weekly Update on October 12, 2007. It was made available for download on Xbox Live Marketplace on December 11, 2007. Rat's Nest includes numerous vehicles but players do not necessarily 'need' them, as the corridors throughout the level are only a short walk. It is made to resemble the campaign level Crow's Nest, with internal vehicle accessible roads, tight corridors, walkways suspended above areas and vents. In the distance, Pelicans and possibly Hornets pass by.

On November 19, 2007, Microsoft released information regarding the first Halo 3 Heroic Map Pack. Rat's Nest was one of the maps included in this bundle. The map pack retails for 800 Microsoft Points ($10 USD), and was released on December 11, 2007. It was codenamed 'John Carpenters Prince of Dorkness'.

Description
This map is, essentially, a big figure 8 track. The map is very open and vehicle-based around its perimeter and center, with close combat and medium sized rooms everywhere else. It has two Warthogs and Mongooses parked outside of both bases, and small rooms connecting each base. On the edge of the road, there is a small outdoor road. On the upper road there is a Ghost and Sniper Rifle, below that Active Camo, then a Gravity hammer and a machine gun turret above that, providing a commanding but exposed view, then the Rocket launcher by the cliff. A Pelican is positioned on a landing platform visible from the track, but it is unusable and unaccessible due to death barriers. Pelicans and Hornets fly by in the distance.

Trivia

 * If you listen closely to the big green pipes, you can hear Drones flying and bumping into each other inside the pipes. This is no doubt in regard to Crow's Nest were you first hear Drones passing through the pipes, before breaking out and engaging the player.
 * Bungie stated in an update that the level includes actual rats. While there are indeed rats, they are dead, most likely due to the radar blip they create could confuse and distract players.