Energy stave

The Energy Stave is a Covenant weapon. It is a melee weapon used exclusively by the Honor Guards. They look like a normal, metal staff, but have a series of glowing orange panels near the top.

Background
These weapons are long staves with a spear-like end that is similar in color to the "fins" of their wielders. Not much is known about these exotic weapons, except that they have a length of 427.5 centimeters, or about 14 feet. They do not seem to have much of a combat purpose but more a ceremonial one, as the Honor Guard will use Plasma Rifles and Energy Swords in real combat. However, they were used by Brutes to subdue/knock out any Grunts and Jackals that came too close to the Council Chamber during one of the High Prophet of Truth's sermons regarding the discovery of the Index. This weapon is never used in gameplay by other characters.

Appearances
They can be seen in the hands of the Brute Honor Guard during both the opening and closing cinematics of the Halo 2 level Gravemind, but they are tossed aside, as the Brutes prefer their own weapons to safeguard the Hierarchs.