Gameplay:
- The Hidden uses Arena rules, but pits a lone Spy (as the titular "Hidden") against everyone else on the server.
- The lone Spy possesses some special abilities, such as increased health, jump height, and speed, as well as a longer Cloak duration and an area-of-effect "Scare!" (causing the enemies to be stunned, akin to the Boo! taunt from the Horseless Headless Horsemann).
- The "Hidden" is cloaked at all times, apart from when attacking. The Cloak slowly drains, but is replenished if the Hidden makes a kill.
- Increased health points for Hidden.
- Increased movement speed for Hidden.
- Increased jump height and distance for Hidden.
- Reduced effectiveness of certain weapon effects against Hidden, e.g. fire, jarate, bleed.
- Hidden is almost always cloaked. Except when attacking, pouncing, taking damage.
- attack2 bind lets Hidden super-jump/pounce
- reload bind lets Hidden stun team Iris players.
- Spys have been disabled.
- Pyros have been disabled.
- Heavys have been disabled.
- Healthkits and ammo boxes have been blocked.
- Sentry guns have been blocked.
- Iris teammates can be seen with objective glow.
- Hidden's killer gets to play as the Hidden next, or a random player is selected.
- Map nominate: !nominate
- Server list: !servers
- Third person view: !tp
- First person view: !fp
- 30 minutes gameplay per map
- End of map vote
