Hidden

Fun mode: Hidden is the first part of Fun mode event in Counter-Strike Online. It is released on 1st week of January 2012 in Korea version.

thumb|300px|right

Overview
Once again, Counter-Terrorist and Terrorist must co-op to face a new enemy called the Joker (Mr. Hidden for some version). This mode is only playable in its exclusive map, Harlem (Hidden City for some region) with a maximum of 10 players in a match.

Gameplay
In a round, one player will be chosen as the Joker. The Joker is fully-invisible when stationary while half-invisible when moving. He is only armed with the Joker stick. Thus, he has high move speed and jump, have 300 health points and 100 armor points. He is also a little taller than players.

For humans, the humans must search-and-destroy the Joker. The player that succeeded to kill the Joker will become the next Joker.