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The Corpse Mill

The adventurers stare into a dark cavernous room. In the distance they hear the grinding of stone quickly dragging closer. A massive wall slides across the open passage way entering the chamber. 6 seconds pass, and another wall grinds by. Every 6 seconds, the pattern repeats.

This room is considered a lethal complex trap and requires that all the players roll for initiative.

Details:

1. The Mill

The spokes of the mill are walls that stretch from floor to ceiling, leaving only enough gap for tiny creatures like rodents or insects to hide in the cracks of the cobble stone, and have the wall pass over them safely. These spokes are spinning counter-clockwise at 90° every 6 seconds. In the turn order, rotate the mill after every turn.

If a player ends their turn inside the circle, or travels clockwise against the spokes, they get hit by the wall. Move the player's token on the map to the next 45° spoke on the map. The player can make a DEX save (DC11) to brace themselves for impact. If the player cannot see within a 10ft radius around them (because they lack darkvision or a light source), they automatically fail the save. On a failed save, the player is knocked prone, and they take 2d10 bludgeoning damage. On a success, they take 1d10 bludgeoning damage, and remain standing.

Every turn they end within the circle, they get dragged to the next 45° spoke on the map and take another 1d10 bludgeoning damage.

This Trap is Deadly Due to the nature of this trap, a player will continue to take damage after their turn. Depending on the number of players in the party, they could very well be killed before their turn ever comes next round. Use this puzzle very carefully.

The other players can easily save each other if they work together, and it is easy enough to pass through without taking any damage at all if the players know all the tricks ahead of time. Use that knowledge to your advantage to scale the difficulty of this room. For max difficulty, throw an evil party in here who doesn't like or help each other, and don't warn them about anything. For absolute ease, allow them to see the whole map, including the kobolds.

2. Trip Hazards

At both the top-right corner of the room, and bottom right corner of the room is a small crack just big enough for a small creature to fit through. Behind the crack is a small cave that connects to the 2 safe pockets at the top and right of the map. Those entrances are also too small for a medium creature to enter. Behind the cracks that face the mill is one kobold each with a bola or net.

As soon as a player is within range from the crack, the kobold throws the bola, and hides. The player can make a DEX save (DC13) to dodge the incoming bola. If the player cannot see within a 10ft radius around them (because they lack darkvision or a light source), they roll at disadvantage because they can hear the spinning bola incoming, but can't see which direction. On a failed save, the player is knocked prone.

3. Safety

On the top and right side of the circle, there is a small 10x15' pocket where a creature can stand and not be in the way of the rotating walls. On the bottom of the circle is the 15' wide entrance, and on the left is the 15' wide exit making there a safe place to hide every 90° or 60ft.

4. Loot

In the first safety pocket on the right side of the map is a small stash of kobold supplies. I gave my players, a speed potion, some poison and some health potions, and an enchanted sling, but you may find something more fitting. Inside the small caves that the kobolds are hiding in is a good place to hide some supplies too. Maybe some ammo or rations. I never intended the players to look inside said cave, but if your party is all gnomes and halflings, they very well might.