Needle cannon

The Heavy Needler is a much larger and more powerful version of the Covenant Needler found on certain vehicles and turrets. The Heavy Needler can be used to assault ground troops, however its main function is to take out enemy aircraft. These three foot long needles, 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 then 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 Needler is replaced by the AA Wraith Fuel Rod Cannon as an anti-aircraft weapon in Halo 3.
 * The Gorgon, a deleted Covenant vehicle set to appear in Halo Wars, had a Heavy Needler for a body.