Voltaic Rift

You conjure forth a 15-foot-radius sphere of lightning centered on a point you can see within range. Whenever a creature attempts to exit the sphere, it must make a Strength saving throw. On a failed save, the creature takes 2d8 lightning damage and is pulled to the center of the sphere, as a lash of lightning yanks them back. A creature cannot take damage in this way more than once on a turn. Creatures wearing metal armor and constructs made from metal have disadvantage on their saving throw against this spell.

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