Fan Pit (CR 6)
The floor of this long hallway is made of wood. A glass window is in the center of the hallway.
Type: mechanical; Perception DC 22; Disable Device 19
Trigger location; Reset None
If the window is opened, the fan activates, pulling the character down into the pit. The pit drops 10 feet into a fan, and then another 20 feet. Pit (DC 22 Reflex Save or take 3d6 damage, +12 melee attack or take 4d8 damage from fan)
With the simple addition of an element (the fan) a normal trap takes an unexpected twist. By adding the fan, you've added an extra layer to a familiar trap. If you do this early, you can use this to help set up later encounters and elements, especially if your party has fallen into an exploration rut. This just might prod them to probe on layer deeper, which opens up your plot and design possibilities.