The room is circular, with at least one exit aside from the one the players entered through. The ceiling must be slightly higher than the room’s radius. The walls, floor, and ceiling are all of flagstone.
In the center of the room is a chest-high obelisk, perhaps 8 inches on each side. Atop the obelisk is a Y shaped piece of brass. There is an axle between the prongs of the Y, which supports a rotating stone disk with a flagstone pattern carved into it. When the players enter the room, the flat sides of the disk are oriented up and down.
The flagstones of the walls also have an odd pattern to them. Every 3ft or so, there is a perfectly circular stone, creating a sort of “polka dot” effect. This element of the room is purely decorative, but serves as an important red herring to obfuscate the room’s trick.
Rotating the disk atop the obelisk has no effect, until it has been rotated a full 180 degrees. So that the side which once faced up, is now facing down. A loud “clicking” sound will reverberate through the room, and the entire floor of the room will flip over, revealing an identical floor and identical obelisk on the other side.
Any occupants of the room will, of course, be dropped into a pit.
If the walls around the edge of the room are examined, players may notice vertical scratches on the walls near to where they meet the floor. If the players follow the scratches around the room, or specify that they are examining the wall 90 degrees from the room’s entrance (where the axle would be mounted) then they will find that the scratches have made a sort of half-circle.
There is no visible gap between the walls and floor which is any more pronounced than the gaps between any of old, cracked and worn flagstones. However, water or sand could be used to discover that the small space between the wall and floor doesn’t “fill up” as it ought to.
This room COULD be used to drop players into a deadly pit, but I would recommend against it. Because, while I don’t think this room robs the players of agency, it IS a little bit cheap. (I considered having the players sense a slight wobble as they stepped into the room, but that just felt painfully obvious for a trap which must already rely on a red herring).
Instead, this room ought to drop the players into a new section of the dungeon. With their pre-explored escape route forever lost to them, exploring the dungeon will take on a new sense of urgency. How long will their food rations last? Can they find a safe enough place to rest each night? Will they ever see sunlight again?
On Monday I’ll post my recommendation for a good room to drop the players into.
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