Zo'op-pattern Weevil

Were you looking for the related articles Anti-Aircraft Battery or Covenant Air Artillery? The Covenant Artillery is a ground-based Covenant field artillery piece. It fires bolts of plasma in indirect parabolic trajectories, and is essentially a larger version of the plasma mortar mounted on Wraiths.

Halo 2 E3 Demo
The Covenant artillery gun was first seen in the Halo 2 E3 Demo. When the Covenant invaded Mombasa, they stationed a handful of artillery pieces on the ground, which demolished UNSC buildings. Eventually, SPARTAN John-117 and a group of Marines encountered one, and Sergeant Marcus Banks called in an air strike to destroy the stationary mortar. The artillery battery is much larger in the demo than its retail version counterpart.

Halo 2
The roles of the artillery guns as an active part of the Covenant assault were greatly downgraded in the retail version of Halo 2, as the levels featuring the guns were completely redesigned. Several artillery pieces are deployed on the beaches of Old Mombasa in the level Outskirts, but none of them are seen being fired during gameplay.

Trivia

 * The Covenant Locust in Halo Wars bears noticeable resemblance to the Covenant artillery battery.