Plasma mortar

The 'Plasma Mortar' is the primary weapon of the Wraith and the Covenant Air Artillery.

Introduction
The Plasma mortar fires huge balls of slowly moving superheated light-blue plasma with a large explosion radius and slow rate of fire. It is extremely powerful, usually kills infantry in a single hit and can destroy just about anything on the battlefield in a minimal amount of shots. Its plasma projectile moves relatively slowly, making it more susceptible to gravity, causing it to fire in an arc, like the Fuel Rod Gun, which allows for it to simply go over obstructions such as barricades and hills.

Tactics

 * Plasma mortar fires in an arc so don't aim straight at the target, aim above the target. The further away you are, the higher you will have to aim to actually hit the target.
 * It is easy to see a plasma bolt coming towards you; if you look up and see a giant light-blue ball of energy in the sky coming towards you, run away or strafe to the side. Due to its slow-moving nature, it will take longer to reach you than a human projectile, so if you see it early you are in with a chance.
 * Remember that even if you are behind cover, you may still not be protected from the plasma's curved trajectory.

Covenant Artillery
A giant stationary plasma mortar was seen destroying buildings in the Halo 2 E3 Demo video. Sergeant Banks called in an airstrike and a group of Longsword fighters flew in and destroyed it.