Volcano

Choose a point you can see on the ground within range. A fountain burning, molten magma erupts in a 20-foot cube centered on that point. Each creature in that area must make a Dexterity saving throw. A creature takes 6d8 fire damage on a failed save, or half as much damage on a successful one. Additionally, a creature is restrained until the spell ends, as magma hardens around it. A restrained creature can use its action to make a Strength check against your spell save DC, freeing itself on a success.

At Higher Levels. When you cast this spell using a spell slot of 6th level or higher, the damage increases by 1d8 for each slot level above 3rd.