Rock Deadfall
A tripwire is stretched just 3 inches off the ground between a pair of load-bearing stones. When it is pulled the wire snaps and causes a small avalanche of rocks.
Rock Avalanche. Creatures within 10 feet of the creature that triggered the trap make a DC 15 Dexterity saving throw . On a failure, the creature takes 3d6 bludgeoning damage and falls prone . On a success, the creature takes half as much damage and remains standing.
Trap. This trap can be detected by a passive Perception of 13 to notice either the construction or the thin, taut tripwire. If the trap is not detected, it automatically triggers a critical failure.
A group Acrobatics or Athletics check allows the adventurers to avoid the tripwire, or an Engineering check can prop up the rocks and effectively disarm the trap. Alternatively, a thieves’ tools check can disable the trap but has disadvantage due to the condition of the tripwire.
Critical Failure: The adventurers are all in the Rock Avalanche area when the trap triggers.
Failure: The adventurer is in the Rock Avalanche area when the trap triggers.
Success: The adventurer disarms or evades the trap.
Critical Success: The party evades or dismantles the trap. Roll on the Boons and Discoveries table (page 196 in Trials & Treasures).