Calamitous Shadow Mist

Dark and powerful tendrils of shadow erupt from a surface within range to fill a 15 foot cube. All other creatures in the area must make a Constitution saving throw. On a failure a creature takes 6d4 necrotic damage, or half as much damage on a successful one.

At Higher Levels. When you cast this spell using a spell slot of 3rd level or higher, the damage increases by 2d4 for each slot level above 2nd.