Instructions
Load the "Five" zombie map in the "Call of Duty: Black Ops" zombie multiplayer section.
Play the game as you normally would until you turn on the power. The power switch is located in the basement labs. Keep opening doors until you get to the teleporter in the big room. Go through it to get to the power switch.
Continue playing the game normally until the warning sound goes off telling you the Pentagon is in lockdown mode. The Pentagon Thief will now appear and begin chasing one of the players (which player he appears to is random). To the other players the Pentagon Thief will appear only as a dim streak of moving light.
Shoot at the Pentagon Thief with your most powerful weapons and have the player who he appeared to run in a loop around the area as fast as he can, turning and shooting at him when possible. The Pentagon Thief is trying to steal that player's weapons and will do so if he catches him. Every player is able to damage him even if he only appears to them as a streak of light, so every player needs to shoot. After a few moments of taking direct shots the Pentagon Thief will die.