The Covenant pylon is a Covenant structure seen in Halo: Reach in the campaign level Nightfall. It creates a field that blocks any and all UNSC scanning equipment in order to conceal any Covenant forces stationed within its "dark zone."
The building is a dark blue color and has a tripodal construction with three legs, three gunnery platforms, and three curved spines on the top of the structure that slowly spin. These spines emit pulses every few seconds as they spin. A small walkway encircles the whole building. There are plasma cannons on each of the three platforms used to defend the pylon. There is a small gravity lift underneath the Pylon similar to that of the lookout tower that allows access to the gunnery platforms. Unlike the lookout tower's lift however, the Pylon's lift has only one exit rather than sending someone up to any part of the platform. This allows the person to be protected by the inside of the Pylon as they ascend. The plasma batteries that provide power to the Pylon are stored in the Pylon's three legs.
The Covenant deployed many of these structures, though only one is encountered in game, on the planet Reach in order to hide their Spires from detection. One such Pylon was discovered during a reconnaissance mission involving Noble Six and Jun. The Spartans, along with a few local militia, were able to eliminate the Covenant forces surrounding the structure and plant a remote detonation charge in the Pylon's power supply. The Pylon was detonated the next day at the start of the Battle of Viery by Kat.
- The Pylon is located near the area that is used for the multiplayer map Powerhouse.
- Although the pylon is supposed to block all UNSC scanning equipment, it does not block Noble 6's motion tracker. This may be for gameplay reasons.
- It is also possible however that the field generated is more like an umbrella in that it only stops UNSC scans from getting in, but once inside they are capable of functioning normally.