Needle cannon

The heavy needle cannon is a much larger and more powerful version of the Covenant Needler found on certain vehicles and turrets. The heavy needle cannon's primary use is to assault ground troops, but it is also quite effective in taking out enemy aircraft as well. These three foot long crystalline explosive projectiles, like the smaller version's, home on to enemy targets, embed themselves into that target, then detonate, causing devastating damage to the aircraft. In the prologue of Halo: First Strike, the Covenant camp started to fire on Fred-104 and Kelly-087 with the Heavy Needler after the Spartans delivered the nuke into the ship in the stolen Banshees. Joshua-029 was killed by them. Fred described them as being like regular needles, but about 3 feet long.

Description
The Heavy Needler is featured in Halo Wars, and is the main weapon of the Vampire, a Covenant Air vehicle. The Heavy Plasma Turret can be upgraded to feature this weapon as well if you choose to upgrade the turret with an Anti-Air weapon.

It was vaguely mentioned in Halo: First Strike, described by Fred as a larger version of the normal Needler round (about three feet long). The Heavy Needler is mainly used by the Covenant as an anti-aircraft weapon. Its projectiles are very effective against aircraft, homing on to the target, embedding itself, then detonating.

Trivia

 * It seems the heavy needle cannon was replaced by the AA Wraith Fuel Rod Cannon as an anti-aircraft weapon during the events in Halo 3.
 * The Gorgon, a deleted Covenant vehicle set to appear in Halo Wars, had a Heavy Needler for a body.
 * It is possible that the heavy needle cannon was developed by the Covenant from the Enforcer's main weapon.