Boulder crash

you create a 20 foot radius boulder in an unoccupied space in the air within range. The boulder then falls to the ground, fracturing into many smaller boulders.Each creature in the boulder's space when it hits the ground makes a dexterity saving throw, taking 12d8 Bludgeoning damage on a failed save or half as much damage on a successful one.A creature within a distance from the boulder equal to twice the boulder's radius makes a Dexterity saving throw. On a failed save, the creature takes 6d8 Bludgeoning damage, has the Prone condition, and is buried in the rubble, requiring a DC 20 Strength (Athletics) check as an action to escape. On a successful save, the creature takes half as much damage only.

Using a higher level spell slot: when cast with a 9th level spell slot, the boulder's radius increases to 30 feet.