Wondrous Item, legendary
This twine will retract when fully unraveled from its spool. If a creature is holding each end of it, the one holding the end of the twine will be pulled to the one folding the spool. The creature holding the end of the twine must make a DC 15 Constitution saving throw or suffer 3d4 force damage.
If a creature is entangled in it while it is retracting, it must make a DC 18 Dexterity saving throw to avoid being strangled by the twine. A failed save takes 5d4 force damage, a saved takes half as much and avoids being trapped by the twine. If a creature becomes entangled, they are considered grappled and must escape.
Spools begin at lengths of 100 feet.