Ghost

Ghosting is a hack similar to OPK, where a player can "invisibly" hit another player from a good distance away. The hack makes the player who uses it a "ghost" that attacks other players, but they can't seem him/her. The Ghoster normally just knives all his enemies, especially in Quarantine, since the Infected cannot hit them. If they were in a serious mode, they would probably go for more Headshots. Note that Ghosting CAN be dodged, if careful.