You evoke incredibly hot flames into a curling sphere and hurl it towards one target you can see within range. Make a ranged spell attack against the target. You have advantage on this attack roll. On a hit, the target takes 10d8 + 60 fire damage, or half as much damage on a miss. Hit or miss, the spell ends, and each creature within 10 feet of the target must succeed on a Dexterity saving throw or else take half of the spell's damage.

Alternatively, you can choose to gather extra energy before releasing it for the attack. On your next turn, if the spell has not ended, you can use an action to gather even more energy or to make the attack. On your following turn, until the spell ends when the turn ends, you can still use your action to make the attack.

Each time you gather energy in this way, wild streams of explosive flame lick out and strike at five creatures or objects within 60 feet of you. Each target must make a Dexterity saving throw. On a failed save, a target takes 12d6 + 15 fire damage.

The spell's damage increases by 25 for each turn that you gathered energy. If you gathered energy for two turns and you used your action to make the attack, you also gain advantage on the attack. If the spell ends and you haven't made the attack yet, you can use your reaction to do so with disadvantage, but if you miss, the target takes no damage from the spell.

This spell damages objects within the area of the attack, and ignites any flammable objects in the area of the attack that aren’t being worn or carried or that take damage from the spell. The caster also sheds bright light in a 30-foot radius and dim light for an additional 30 feet until the spell ends. Any creatures killed or objects reduced to 0 hit points by this spell are reduced to ashes.