Bromley's Pocket Boulder

You mark a Tiny pebble or stone with an arcane rune before throwing it or launching it using a sling at a point you can see within range. As the pebble flies through the air, it transforms into a Small boulder, which crashes down at the point you chose. Creatures in a 5-foot cube area must make a Dexterity saving throw, taking 1d10 Bludgeoning damage on a failed save or half as much damage on a success.

A creature that is smaller than the boulder that fails its saving throw is also knocked Prone and Restrained as it gets pinned underneath the boulder, until it or another creature within 5 feet of it makes a successful Strength (Athletics) or Dexterity (Acrobatics) check to pull itself out from under it.

Objects in the boulder's area when it lands that are not being worn or carried are crushed, taking double the amount of damage from this spell.

A pebble or stone is permanently changed into a non-magical boulder by this spell, occupying the area until it is moved or destroyed.

At Higher Levels. When you cast this spell using a spell slot of 2nd level or higher, the size and damage of the boulder increases; the cubic area grows by 5 feet in each dimension and the damage dealt to creatures and objects increases by 1d10 for every spell slot level above 1st.