Plasma torpedo
From Halopedia, the Halo wiki
Plasma Turrent
The plasma turrent is a powerful covenant starship weapion. It is used in most UNSC engagements and is very deadly in combat. It fires a spear of Plasma and can strike at almost any range, upon contact it causes sever damage to a targit and can be used in conjusion with the Plasma torprdos, and energy projectors to desamate an entire human fleet. The turrent itself is insect antena like in apperance and is located along the sides of the ship. The beam itself is blue and short and has a ball like head. All covenant ships have them.