Voltaic Cloud

You create a 10-foot cube filled with a cloud of roiling electric energy centered on a point within range.

Each creature completely within the cloud at the start of its turn must make a Dexterity saving throw against lightning damage.  The creature takes 2d8 lightning damage on a failed save, or half as much damage on a successful one.

Creatures that are wearing metal armor have disadvantage on this saving throw.

On your turn, as a action, you can choose to move the cloud up to 30 feet.

At Higher Levels. When you cast this spell using a spell slot of 3rd level or higher the damage increases by 1d8 for each slot above 2nd level.