The Sovereign Gatecrusher
A heavy, reinforced adamantine-coated steel slab hidden within the ceiling of a narrow passage or archway. It is powered by high-pressure steam and hydraulic cylinders designed to drop at terminal velocity.
The Sovereign Gatecrusher
Defenses
Detection
“An ornate stone archway decorated with relief carvings of weeping angels. Above the crown of the arch, a thin, almost invisible seam in the masonry reveals the location of the descending block.”
Standard Engagement
A pressure plate located under the central cobblestones of the archway. It is calibrated to trigger only if 100 pounds or more are placed upon it.
None. On trigger, the slab falls instantly and then remains in place until the hydraulic system pulls it back up.
The trap automatically resets after 1 hour as the steam boilers build back sufficient pressure to retract the slab.
When triggered, the slab falls. Each creature beneath the slab must make a DC 18 Dexterity saving throw. On a failure, a creature takes 66 (12d10) bludgeoning damage and is knocked prone and restrained under the slab. On a success, a creature takes half damage and moves to the nearest unoccupied space outside the slab's 10-foot by 10-foot area.
A creature restrained by the slab can use an action to make a DC 25 Strength (Athletics) check to lift the slab enough to crawl out. Another creature can use its action to assist, granting advantage on the check.
The slab is reinforced with adamantine. Any critical hits against the trap's HP while it is in the ceiling or fallen have their damage reduced to normal hits unless the weapon used is also adamantine.
The mechanism is exceptionally quiet. Unless a creature has a Passive Perception of 22 or higher, they have disadvantage on the Dexterity saving throw if they were not aware of the trap before it triggered.
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