As an action, you create a sphere twice as big as normal of sand centered on a point within 20 meters. The sphere spreads around corners, and its area is heavily obscured. It lasts for the duration or until a wind of moderate or greater speed (at least 15 kilometers per hour) disperses it.

Augment

Choking Sands. You can expend 1 additional mana and cast this spell as two actions to cause the sands to fill the lungs of creatures within it. The sphere is now sized based on the mana expended and the duration changes to 5 minutes/mana.

Each creature that is completely within the cloud at the start of its turn must make a Fortitude saving throw.

On a failure, the creature spends its actions that turn coughing up the sand in its lungs. Creatures that don’t need to breathe automatically succeed on this saving throw.