You raise your hands to the sky, forming a blazing sphere that unleashes a beam of intense flame. Choose two points within 120 feet of each other within range, and the beam blasts outwards, moving from one point to the other, forming a 5-foot wide line of destruction between the points. Creatures in the area must make a Dexterity saving throw. A target takes 10d6 fire damage on a failed save, or half as much damage on a successful one.   In addition, the area inside the line becomes unstable. At the start of your next turn, it explodes in an aftershock of lava. Each creature inside the line at that time must make a Dexterity saving throw. A creature takes 12d6 fire damage on a failed save, or half as much damage on a successful one. Also on a failed save, a creature is knocked prone.