Erupting Earth

A fountain of churned earth and stone erupts
in a 20 ft cube. Each creature in that area makes
a Dex save. A creature takes 3d12 bludgeoning
damage on a failure, or half as much on a success.
The ground in the area becomes difficult terrain.
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.