Dust of Dryness

This vial contains 9 pinches of dust. As an action
you sprinkle a pinch over water. The dust turns a
cube of water 15ft on a side into one marble-sized pellet, which floats or rests near where the dust
was sprinkled. As an action, you can smash the
pellet, causing the pellet to shatter and release
the water absorbed. An elemental composed of
water that is exposed to a pinch of the dust must
make a DC 13 Constitution saving throw taking
10d6 necrotic damage on a failed save, or half as
much damage