Here is another installment of exTRAPaganza, our Thursday over-the-top trap series.
All of the doors, doorways, arches and windows have a dark, hazy mist swirling around them.
Every time a door or window is opened, or a doorway or archway entered, a 5 ft pillar of darkness appears in the space. This deals 9d6 damage to anyone in the pillar, and 2d8+9 points of damage to anyone who touches it. It also creates darkness in a 30′ radius, and reduces the light level by 1 step for the next 30 feet. The pillar lasts for 9 rounds.