The Guardians

From Halopedia, the Halo wiki

Summary

In both Halo 1 and Halo 2, when a player in multiplayer is killed inexplicably (i.e. by a physics glitch, by the environment, or by an AI in Halo: Custom Edition), the message reads "_player_ was killed by The Guardians". There are also ways to do this among players (guardian glitch). For example, aim at a teammate's head with a Battle Rifle (or a Pistol or Carbine), right trigger and Y simultaneously until he dies. Another way is when a player is killed by a melee attack from another player who died just as they did the melee attack. Also being killed in & out of maps by unmanned vehicles has been known to cause this and has resulted in an unexplainable maniacal laugh being heard on occasion.

Notes

  • If you do this right, it should show the weapon firing, come down, then immediately fire again without seeing the secondary weapon.
  • Friendly fire must be off to do a guardian glitch on your teammate. Shields off will produce optimal results, but it is possible to guardian glitch with full shields by doing the glitch repeatedly.
  • Doing this while moving will result in you dying instead of your teammate.