|Effects||Allows the room host to play Nightmare|
|Cost to buy||N/A|
|Date added||Alongside Nightmare|
A key with strong zombie energy surrounding it. It is rumoured that the holder of this key will fall into deep sleep where fearsome nightmares await.
This key must be owned by the room host to play Nightmare. Nightmare keys now can be obtained by simply clearing Zombie Scenario Season 1 maps.
- Indonesia: 2 January ~ 16 January 2013. Get 1-day Nightmare Key for free by playing for an hour during the event.
- There is a variant called as "Special Nightmare key" which is exclusive for Counter-Strike Nexon: Zombies. It shares the same function with the normal one, but allows the room host to play a Special Nightmare map, which includes the Teddy Terror.