Panicked Tunnel Collapse
The tunnel groans like a living thing, then buckles in fits and starts as loose stone rains down and the passage begins to cave inward. This is not a sudden total collapse, but a panicked failure of the ceiling that punishes haste, loud movement, and anyone standing in the wrong place when the rock finally gives way.
Panicked Tunnel Collapse
Defenses
Detection
“A section of old stone tunnel has split along hairline cracks, with dust sifting from the ceiling in nervous little puffs. The floor is littered with fresh pebbles, broken mortar, and a few bent pick marks where the rock is already giving way.”
Standard Engagement
A creature enters the weak section, thunderous force rattles the passage, or the tunnel is otherwise disturbed by loud impact or combat.
If a creature enters the unstable section, starts combat there, or makes a loud disturbance such as thunder damage, a shockwave spell, or heavy impact, the ceiling begins to fail. On the hazard's initiative, loose stone falls and the area becomes difficult terrain. At the end of that round, the rubble fall effect triggers in the section.
The hazard does not reset on its own. Once collapsed, the passage remains blocked until cleared or repaired.
Each creature in the affected 10-foot-long section must make a DC 13 Dexterity saving throw. On a failure, the creature takes 3d6 bludgeoning damage, is knocked prone, and is buried in loose rubble. On a success, the creature takes half damage and is not knocked prone.
A buried creature is restrained and has total cover from attacks originating outside the rubble. The creature can use its action to make a DC 13 Strength check, escaping on a success. Another creature can also clear enough debris to free it with 1 minute of work.
A creature that spends its movement dashing, fighting, or otherwise causing violence in the affected section has disadvantage on checks made to notice or stabilize the hazard until the end of that turn. Panic makes the collapse worse, not better.
If the party takes a round to move carefully and no creature runs, shouts, or slams the floor, the DM can allow a DC 13 group check using Wisdom (Perception), Intelligence (Investigation), or the appropriate tool to hold the collapse at bay long enough to pass one by one.
Turn Panicked Tunnel Collapse into a sheet
A high-res, share-ready sheet you can post or print.