Mirror look a like, Horzine traitor. One of the zed players spawns with the same weapons and perk settings as one of the players. They are wearing the exact same cosmetics and can use the same guns. This happens during the attack waves so while the normal players are fighting the traitor can move in close and then attack. It oculd be too powerful but it certainly would add a huge twist to PVP. Probably to difficult to impliment, but something to consider for KF3.