Gas Vacuum Trap
A chest rests on the floor of a spotlessly clean, high-ceilinged room. A faint shimmer of magical force blocks the doorway into the room.
A Perception or Investigation check, or looking into the room, reveals a cloud of gas roiling near the room’s ceiling. A second magical force field separates the gas from the lower portion of the room. A creature that makes an Arcana check deduces that the magical field blocking the door and the one blocking the gas are two sides of a magical cube of force. The force cube can be destroyed with a successful dispel magic spell or by dealing it at least 50 force damage.
Vacuum. The space inside the force cube is a vacuum. Destroying the cube causes the room to flood with air from outside the room and with poison gas from the cloud above the cube.
Spell Effect. This is an evocation effect created by a 5th-level spell. Casting dispel magic on the force cube triggers a Critical Failure.
Spell Solve. A creature that teleports into the cube is exposed to vacuum but not to the poison gas. Once the force cube is destroyed, a gust of wind or similar effect dissipates the gas.
- When the force cube is destroyed, each creature within 30 feet must make a Strength saving throw . A creature that braces itself against a solid surface before the cube is destroyed makes the saving throw with advantage .
Potential Outcomes
Critical Failure or Failure. The creature is pulled into the room, takes 10 (3d6) bludgeoning damage, and is knocked prone —just in time for the gas cloud to settle over them. A creature that enters the gas-filled area for the first time on a turn, or that starts its turn inside the area, takes 22 (5d8) poison damage.
Success or Critical Success. The creature is not pulled into the room.