Swinging Log (5e Trap)
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This trap uses a tripwire to trigger a swinging log.
The tripwire is 3 inches off the ground and stretches between two columns or trees. The DC to spot the tripwire is 10. A successful DC 15 Dexterity check using thieves' tools disables the trip wire harmlessly. A character without thieves' tools can attempt this check with disadvantage using any edged weapon or edged tool. On a failed check, the trap triggers.
If the trap is triggered, the log swings in a 10-foot line. Each creature in that line must succeed on a DC 14 Dexterity saving throw or take 5 (1d10) bludgeoning damage be pushed up to 10 feet backwards and be knocked prone.
The log has AC 15, 18 hit points, resistance to bludgeoning and piercing damage, and vulnerability to fire damage.