Bag of Rats

While attuned to this item, the holder of this bag may, as an action, turn it upside down and unleash a fearsome wave of rats. When the bag is turned upside down, rats swarm out from the user in a 15 ft radius circle. Every creature in the range of this effect must make a DC 15 Dexterity Saving Throw or take 4d4 Piercing damage. Creatures moving through the swarm treat the effected area as difficult terrain. The attuned user of this bag may use their subsequent action on following turns to expand the area of the bag and force all creatures inside to repeat the Dexterity Saving Throw. The bag expands by 5 ft on each subsequent turn until the total effective range of the swarm reaches a 30 ft radius.

Notes: Requires attunement by a Druid.