call of the lightning dragon

you raise your hand in the sky calling for the storms to hear you . casting down a dragon of lightning to strike all your foes. you chose to either strike one enemy for 8d8 in a 50ft range.enemies in a 5ft range of the target will take 2d4 damage as well. you can also split the dragon sending into four enemies for 2d6 damage each. each enemy has to take a saving roll of 15 or will be stunned for 2 turn.