Elemental Cube

When you cast this spell, a five foot by five foot cube appears hovering two feet off the ground, up to thirty feet away. Any being in the cube as it is cast, must succeed a DEX saving throw or take 8d8 acid, cold, fire, lightning, necrotic, or radiant damage (your choice). On a success, the target takes half this damage. Any creature who enters the cube radius takes the damage as previously chosen, no saving throw required.

At higher levels, for each spell slot above the fifth, add one die of damage.