Wall of Quicksand

You create a wall of sucking quicksand at a point you choose within range. The wall is composed of 7 cubes that are each 10 ft wide, 10 ft high, and 10 ft thick. You can place the cubes in any orientation, but each cube must be contiguous with at least one other cube. The wall is opaque and lasts for the duration. When the wall appears, each creature within its area must make a Dexterity saving throw. On a failed save, a creature takes 3d8 bludgeoning damage and is pulled into the wall. The creature is blinded, restrained, and unable to breathe, and has three-quarters cover from attacks outside the wall. While it remains in the wall, it takes 3d8 bludgeoning damage at the end of each of its turns. On a successful save, the creature takes half damage and is not pulled into the wall. A creature that comes within 5 ft of the wall for the first time on its turn or ends its turn there must immediately make a Dexterity saving throw. On a failed save, the creature takes 3d8 bludgeoning damage and is pulled into the wall. A creature that is restrained in the wall can make a Dexterity saving throw at the start of each of its turns, and can exit the wall and move up to half their speed on a success. A creature can attempt to free another creature from the wall by making a Strength check against the spellcaster's save DC.

When you cast this spell using a spell slot of 5th level or higher, the damage increases by 1d8 for each slot level above 4th.