The Ghosts of Halo are anomolies within maps and have been confirmed to exist by some groups. Their reason for being present in maps is unknown at this time, but most of them share common characteristics. These are the lack of a walking animation, not showing up on the in-game scoreboard, extreme accuracy with most or all weapons, always knowing the exact location of the real player(s), and invincibility. Ghosts have been reported on the Halo 2 map Lockout, Halo 3 maps Blackout and Sandtrap, and the Halo: Reach map Reflection, however the Ghost reported on Reflection appears to be a non-Ghost related occurance as a response of lag on Matchmaking (I've seen it in a Team SWAT game when a player was killed). They seem to spawn through extreme lag, such as when the map is overloaded or a player leaves in a Matchmaking game. Some of the Ghosts are capable of perfect accuracy with Plasma Grenades, such as the Ghost of Lockout. It stalked a player in a private game, always throwing Plasma Grenades that stuck every time. This video can be found on YouTube; just look up "Halo 2 Ghost of Lockout." The Ghost of Sandtrap has been said to have the ability to kill simply by making eye contact with a player, while also retaining invincibility. For more information, look up "Ghosts of Halo" on Halo Nation (www.halo.wikia.com).