As two actions, a bright streak flashes from your pointing finger to a point within 20 meters and then blossoms with a low roar into an explosion of flame. The fire spreads around corners and ignites flammable objects in the area that aren’t being worn or carried. Each creature in a sphere centered on that point must make a Reflex saving throw.
On a failure, it takes 6d6 fire damage and is burning 2.
On a critical failure, it takes twice as much damage and is burning 4.
On a success, it takes half as much damage and is burning 1.
On a critical success, it takes no damage.
Augment
You can increase the damage by 1d6 and the burning level by 1 for each additional mana expended.
Delayed Blast Fireball. You can expend 1 additional mana so the ball lingers at the point of origin as a glowing bead while you concentrate on the spell for up to 1 minute. If at the end of your turn the bead has not yet detonated, you can increase the damage by 1d6. When the spell ends, either because your concentration is broken or because you decide to end it, the bead explodes.
If the glowing bead is touched before the interval has expired, the creature touching it must make a Reflex saving throw.
On a failure, the spell ends immediately, causing the bead to explode.
On a success, the creature can throw the bead up to 5 meters. When it strikes a creature or a solid object, the spell ends, and the bead explodes.