Bag of Caltrops (20)

As an Action, you can spread a bag of caltrops to
cover a square area that is 5ft on a side. Any
creature that enters the area must succeed on a
DC 15 Dex. Saving Throw or stop moving this
turn and take 1 piercing damage. Taking this
damage reduces the creature's walking speed by
10 feet until the creature regains at least 1 HP.
A creature moving through the area at half speed
doesn't need to make the save.