Conjunction of Earth

This is an implementation of the Conjunction of Earth spell from Tasha's Crucible of Everything Else

You begin to merge your current plane of existence with a plane of elemental earth in a 30-foot-radius, 60-foot-tall cylinder centered on a point that you can see within range. When you cast the spell, and as your action each round for the duration, you can cause one of the following:

• The surface of stone, dirt, and any other earthen area within the cylinder liquifies and becomes sticky, turning into difficult terrain. A creature that starts its turn on such a surface must succeed on a Strength saving throw, or become stuck to the surface and be grappled until the start of its next turn or until the spell ends. A creature grappled in this way has disadvantage on Dexterity saving throws.
• Stone, dirt, and other earthen surfaces within the area buck wildly. Each creature on such a surface must succeed on a Dexterity saving throw or take 4d6 bludgeoning damage and be moved 10 feet in a random horizontal direction within the cylinder.

This spell has no effect on structures.