Needle cannon
From Halopedia, the Halo wiki
Template:FactOrFiction The heavy needler is first seen in Halo 2 on the level " Sacred Icon." As Tarterus explains to you how to take down a sentinal enforcer. If you stay alive long enough the enforcer will start to shoot out the heavy needlers. The heavy needlers on a enforcer shoots out blood red needles instead of the weaker deep purple variety that the Covenant use. These needles also tend to be larger than the covenant needles that are shot out the lesser needler. Ironicaly, the heavy needlers needles do not explode but still pack quite a punch and can take down the Arbiter quickly. Even though the standard covenant needler is weaker, the covenant also have another varient that is suprisingly more powerful than the varient that sentinal enforcers fire. On the first page of chapter twelve in Halo First Strike it mentions," A hail of purple-white crystalline shards hissed through the air, arcing up from the forest beneath them. Each shard looked like the projectile fired from a covenant needler-but far larger. The shard that slashed past Fred's cockpit was the size of his forearm."