Sentinel beam
From Halopedia, the Halo wiki
Summary
The Sentinel Beam is a Forerunner weapon connected to Sentinels to control outbreaks of The Flood. It appears as a beam of energy that can cut through most forms of the Flood parasite. The blue Sentinel beam is a stronger, more efficient version of the common orange Sentinel beam and overheats less.
In Multiplayer, the Sentinel Beam will only appear in the bases on Backwash.
Combat Usage
The Sentinel Beam is not player-usable in Halo: Combat Evolved. However, it can be used in Halo 2.
The Sentinel Beam runs on an un-rechargable battery with a maximum charge of 100%. Like the Covenant's plasma weapons, it can overheat. It is effective against most kinds of Flood and Sentinels, but ineffective on shielded targets. It also has an unlimited range and be used to attack targets at virtually any distance.
