The Bends

You assault the internal chemistry of a creature you can see within range, causing bubbles of nitrogen to precipitate in its blood, forcing it to make a Constitution saving throw. On a failed save, the target takes 5d8 poison damage and is poisoned for 1 minute. On a successful save, the target takes half as much damage and isn’t poisoned. If the target is completely submerged in water, increase the damage dice from d8s to d10s.

The target can repeat the saving throw at the end of each of its turns, ending the effect on a success.

At Higher Levels. When you cast this spell using a spell slot of 4th level or higher, the damage increases by 1d8 for each slot level above 3rd.