|Trigger: Mechanical: Latch or Switch||Effects:Never Miss|
|Resets: Automatic||Bypass: None (Avoid)|
Description: This is another player killer.
Why have a trap like this?
Mostly to create an environment that threatens high level characters who do not use their resources. If they insist on handling problems the same way they did at first level, this trap is designed to show why a lower level group of characters hasn't already dealt with the problem.
This is a hallway or stairway that is balanced on a fulcrum. When enough weight is put on the dangerous side, the entire hallway swivels dumping everyone on it down into the end of the hallway or staircase. This surface is often covered in spikes.
The hallway is usually a minimum of 140' long. This is to prevent characters from seeing the end of the hallway or stairway, where the spikes are located. The fulcrum point is usually located near the middle. This provides a 70' distance from the center to the wall.
There is a latch on the entrance side that prevents it from swinging down. Once more weight is past the fulcrum then the other side the hallway will swivel, dumping everyone into the spikes at the end of the hall. The fall is the length of hallway to the end, usually 60'-100' feet which is enough to kill most members of the party.
After all the oil, alchemist's fire flasks, wands, and various other items fail their save versus crushing blow, very few members should be alive.
If anyone thinks of it, and if you are kind, you could provide odd metal handholds on the walls. A quick thinking delver could grab one before they fell to their doom.
If you are concerned about this possibility, the hallway swiveling could always trigger a flood of acid or magma.
Detection/Disarming: Sending a scout ahead while someone is standing to counterbalance the hallway is a good plan, otherwise when the trap is triggered, a wall will rise up and they will never see their companion again.
Other methods of detecting the trap include spells, such as Wizard Eye or Legend Lore. Several magical items like eyes of the eagle will also reveal the trap.
X-ray vision and other abilities will note that the space beneath where the hallway will swivel down.
Items and magic such as Feather Fall, winged boots, and contingency spells triggered while falling, can save the party from death.
This trap is a classic, appearing in Tomb of Horrors as well as a variety of other books and sources throughout the years.