This small packet contains 7 pinches of dust.

Dust of Dryness
Type: wondrous item
Rarity: uncommon
Weight: 0.5

You can use an action to sprinkle a pinch of it over water. The dust turns a cube of water 15 feet on a side into one marble-sized pellet, which floats or rests near where the dust was sprinkled. The pellet’s weight is negligible.

Someone can use an action to smash the pellet against a hard surface, causing the pellet to Shatter and release The Water the dust absorbed. Doing so ends that pellet’s magic.

An elemental composed mostly 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 on a successful one.