Blow Up

You flash with a bright light, then blossom with into an explosion of flame. Each creature in a 20-foot-radius sphere centered on you must make a Dexterity saving throw. A target takes 10d10 fire damage on a failed save, or half damage on a successful one.

The fire spreads around corners. It ignites flammable objects in the area that aren't being worn or carried.

You are also effected by the damage from this spell, and if you succeed on the Dexterity saving throw then you take half as much damage as you would have.

If you have been struck by lightning, magical or otherwise, since the last time you slept, this spell deals 20d10 damage instead.