Depth Charge

The pearl floats in front of your pointing finger, before it disappears in a bright streak, flashing from your pointing finger to a point you choose within range, and then erupts with a burbling roar into a 20-foot-radius sphere of swirling water, dealing 1d10 force damage. This sphere of water remains for 1 minute, or until released or dispelled. If any creature inside the sphere attempts to move, each creature in the sphere must make a Constitution saving throw. A target takes 10d8 fire damage on a failed save, or half as much damage on a successful one. The water remains superheated for the duration, and a creature must also make this saving throw whenever it enters the spell's area for the first time on a turn or ends its turn there.

The water spreads around corners. Creatures which cannot breathe under water will instantly begin to drown (suffocate), as the force of the water knocks any air they might have had out of their lungs.

At Higher Levels. When you cast this spell using a spell slot of 9th level, the sphere's radius increases by 10 feet.