Monolith

You summon a massive cube of rock, 30 feet on each side, at a point you can see within range of the spell. Creatures in the area must make a Constitution saving throw with disadvantage. On a failure, an affected creature takes 18d8 crushing damage. On a success, it takes only half the damage. Objects take the damage in full.

The rock shatters on impact, exploding in a 30-foot radius; creatures in that area must succeed on a Dexterity saving throw or take 10d8 incisive damage. All terrain affected by the spell becomes difficult terrain.