Entomb

The ground beneath an enemy softens to a mud-like consistency and begins to engulf and crush them. Choose one creature you can see within range. The target must succeed on a Strength saving throw or be restrained and take 2d8 bludgeoning damage at the start of each of its turns. A restrained creature can attempt a new saving throw at the end of its turn, ending the effect on a success.

This spell has no effect on a creature that is not touching the ground.