138 BLACK CURTAIN. The black curtain stretches from the twenty foot ceiling to the floor and covers from wall to wall. It ripples slightly, as if in the presence of a mild breeze.
Behind the curtain is a gigantic circular fan, and another room can be seen behind the four huge sharp metal blades of the fan. If the curtain is moved, the fan will begin spinning fast creating a substantial wind blowing the characters back towards the hatch door.
It is possible to jam the fan, but it will easily cut most items. Such items will be subject to a crushing blow, as per the Dungeon Master's Guide, page 80. Anyone attempting to merely jump through will be caught on a 1-19 in 20 and take 6d8 damage.
If the curtain is pulled back in front of the fan, the blades will stop and it can be traveled safely.