Crushing Gravity

Choose a point on the surface of the ground that you can see within range. A 20-foot diameter, 30-foot high cylinder of heavy gravity pulls creatures to the ground. Flying creatures are pulled to the ground and their flying speed becomes 0 while within the area. This area is also considered difficult terrain. When a creature first enters the area and at the beginning of each of its turns it must succeed on a Strength Saving Throw or suffer 4d6 points of Bludgeoning damage and be knocked prone. Flying creatures automatically fail this Saving Throw.

For each level of spell slots used to cast this spell beyond 3rd, increase the damage by 1d6.