Wrath from Beyond

Plumes of Hellfire burst out of the ground at four different points you can see within range. Each creature in a 60-foot-radius sphere centered on each point you choose must make a Dexterity saving throw. The sphere spreads around corners. A creature takes 20d8 necrotic damage and 20d8 bludgeoning damage on a failed save, or half as much damage on a successful one. A creature in the area of more than one necrotic burst is affected only once.