Choose a point you can see on the ground within range. A fountain of churned earth and stone erupts in a 20-foot cube centered on that point. Each creature in that area must make a Dexterity saving throw. A creature takes 3d12 bludgeoning damage on a failed save, or half as much damage on a successful one. Additionally, the ground in that area becomes difficult terrain until cleared. Each 5-foot-square portion of the area requires at least 1 minute to clear by hand.
At Higher Levels. When you cast this spell using a spell slot of 4th level or higher, the damage increases by 1d12 for each slot level above 3rd.* - (a piece of obsidian)