In a round, a player will be randomly chosen as the Joker. The Joker is fully-invisible when stationary while half-invisible when moving. He is only armed with a staff. In addition, he has high moving speed and jump, 300 health points and 100 armor points. He is also a little taller than the Counter-Terrorist and Terrorist player models.
For humans, the humans must annihilate the Joker. The player that succeeded to kill the Joker will become the next Joker.
- This mode is based on a Half-Life 2 modification called The Hidden: Source.