You call towards the stormy heavens, attempting to harness electric energy within your body. Make a Constitution saving throw against your own spell save DC. On a failed save, you are struck by a mighty bolt of lightning and take 20d8 lightning damage and are paralyzed, after which the spell ends.
If you succeed, however, you send the power of the lightning into the earth, punching the ground and sending the energy flowing through it. All creatures on the ground within 30 feet of you make a Constitution saving throw. The creatures take 20d8 lightning damage and are paralyzed on a failed save, or half the damage and aren't paralyzed on a successful one.
All creatures affected by this spell, including yourself, have disadvantage on the Constitution saving throw if they are wearing metal.