Cryophobia

With rumbling quakes, you cause a set of icicles to emerge from the ground in a 20 feet cube within range (so long as that area is on a solid surface. Each creature in that area must succeed on a Dexterity Saving Throw or take 5d8 Cold damage and have their speed reduced to 0 feet for the spell’s duration. On a successful save the damage is halved and no other ill effects are suffered. At the end of each of its turns, a creature may repeat the save-ending the effect on themselves on a success.

Any creature that ends their turn in the area whilst the spell is active takes 2d8 Cold damage.

At Higher Levels. When you cast this spell using a spell slot of 4th level or higher, the damage of the initial blast increases by 1d8 for each slot level above 3rd.