With a sweeping gesture, you cause water to swell up into a 20-foot tall, 20-foot radius cylinder centered on a point on the ground that you can see. Each creature in the cylinder must make a Strength saving throw. On a failed save, the creature is restrained and suspended in the cylinder; on a successful save, the creature moves to just outside the nearest edge of the cylinder.
At the start of your next turn, you can direct the current of the swell as it dissipates. Choose one of the following options:

Riptide. The water in the cylinder flows in a direction you choose, sweeping along each creature in the cylinder. An affected creature takes 3d8 bludgeoning damage and is pushed 40 feet in the chosen direction, landing prone.

Undertow. The water rushes downward, pulling each creature in the cylinder into an unoccupied space at the center. Each creature is knocked prone and must make a successful Constitution saving throw or be stunned until the start of your next turn.