Crimson Energy Storm (FV)

The Caster summons a 90 ft cloud of dark mist that floats high above them. Every round, the caster rolls a d10. If the roll is 5, 7, 2, 1 or 0, strike up to three creatures you choose with a bolt of red lightning. They must take a CON saving throw or the lightning stuns them for 1d6 turns and deals 6d6 lightning damage. If they succeed, they take a third of the damage. The cloud lasts until dispelled and cannot be moved.