You manifest the pressure of the deep sea in a 20-foot-cube within range. The area becomes difficult terrain for the duration. Each creature within the area when the spell is cast must succeed on a Strength saving throw or become blinded and restrained for the duration. Each creature that enters the spell's area for the first time on its turn or starts its turn there must also succeed on a Strength saving throw or become blinded and restrained for the duration. A creature has advantage on the saving throw if it has a swimming speed, and automatically succeeds if it is immune to the effects of being underwater at a depth greater than 100 feet.

A creature restrained by the spell that starts its turn within the area takes 1d6 bludgeoning damage, and can use its action to make a Strength check against your spell save DC, ending the spell on itself on a success.

When the spell ends, either because your concentration is broken or because you decide to end it, each creature restrained by the spell takes 1d6 bludgeoning damage for each round that has passed since you cast the spell from the change in pressure.

If you touch a body of water when casting this spell, you can choose a point within 60 feet of you that is in the same body of water. The spell is cast as if you were at the chosen point, but you must use your own senses.