This trap forms a saw-toothed steel ring that snaps shut when a creature steps on a pressure plate in the center. The trap is affixed by a heavy chain to an immobile object, such as a tree or a spike driven into the ground. A creature that steps on the plate must succeed on a DC 13 Balance or take 1d4 piercing damage and stop moving. Thereafter, until the creature breaks free of the trap, its movement is limited by the length of the chain (typically 3 feet long). A creature can use its action to make a DC 13 Fortitude roll, freeing itself or another creature within its reach on a success. Each failed check deals 1 piercing damage to the trapped creature.