Conjure Elemental

You conjure a Large, intangible spirit from the Elemental Planes that appears in an unoccupied space within range. Choose the spirit's element, which determines its damage type: air (Lightning), earth (Thunder), fire (Fire), or water (Cold). The spirit lasts for the duration.

Whenever a creature you can see enters the spirit's space or starts its turn within 5 feet of the spirit, you can force that creature to make a Dexterity saving throw if the spirit has no creature Restrained. On failed save, the target takes 8d8 damage of the spirit's type, and the target has the Restrained condition until the spell ends. At the start of each of its turns, the Restrained target repeats the save. On a failed save, the target takes 4d8 damage of the spirit's type. On a successful save, the target isn't Restrained by the spirit.