Choose a point you can see on the ground within range. The ground in a 30-foot radius circle centered on that point becomes fluid and permeable, creating a roiling sinkhole of mud, sand, and clay. The sinkhole slopes down as it approaches the center, which is 20 feet below the normal surface level of the ground. When the area appears, each creature that is standing on the ground within the area must make a Dexterity saving throw. Creatures with tremorsense have advantage on this saving throw, and creatures with a burrow speed automatically succeed. On a failed saving throw, a creature sinks halfway into the mud and sand, becoming restrained by the sand until the spell ends.

Until the spell ends, the ground in the area is difficult terrain, and any creature who enters the area or ends its turn within the area must repeat the Dexterity saving throw if it is not already restrained by the spell, becoming restrained on a failure. In addition, when a creature ends its turn while restrained by this spell, it is pulled up to 10 feet along the surface toward the center of the sinkhole.

A creature restrained by the sinkhole can use its action to make a Strength or Dexterity check (its choice) against your spell save DC. On a success, it frees itself and climbs onto the surface of the moving ground.

When the spell ends for any reason, the ground solidifies and the terrain returns to how it would have been if the spell had never been cast. Each creature who is restrained by the spell when this occurs is suddenly crushed by solid stone and rock. It becomes grappled, and is restrained while grappled in this way. They also must each make a Constitution saving throw. Creatures within 10 feet of the center of the sinkhole have disadvantage on this saving throw. On a failed saving throw, a creature takes 8d6 bludgeoning damage. On a successful saving throw, a creature takes half damage.

The escape DC for creatures grappled as a result of this spell equals your spell save DC, and targets are grappled by the ground itself, not by any creature or spell.