Crewman

Crewman is the third enlisted rank of the UNSC Navy, equal in rank to Lance Corporal in the UNSC Marine Corps. Glitch:

In Halo: Combat Evolved, on the first level (The Pillar of Auttmn), after Captain Keys gives you the Pistol, walk out the Bridge and out the door you would usually go to. The Pistol will show up. Walk over to the next door and shoot the three grunts that appear. Come back to the Bridge.

Now, shoot at the Crewman that are standing on their head with the Pistol. They will die, but instead of a "Sniped" death animation, they will die as if an explosion killed them. Cortana will not call for the Marines that usually come and try to kill you when you friendly fre. You could shoot at the corpse of the Crewman with blood coming, instead of the bullet going through them and hitting the ground. You could also melee their corpses, and blood will also come.

Also, if you shoot the heads of the Crewman that are sitting down by their stations, they will become invincible.