Xanathar's Guide to Everything P. 160

Maelstrom

5-level Evocation

A swirling mass of 5-foot-deep water appears in a 30-foot radius centered on a point you can see within range. The point must be on the ground or in a body of water. Until the spell ends, that area is difficult terrain, and any creature that starts its turn there must succeed on a Strength saving throw or take 6d6 bludgeoning damage and be pulled 10 feet toward the center.