Amaterasu

A powerful torrent of powerful black flame erupts from the caster’s arm, burning the arm away and dealing 2d6+1 fire damage to the caster,  but unleashing fire up to 100 ft in the direction of the casters choice. This blast will set fire to anything it touches, burning it to ashes in a couple turns (count varies with object). This flame will spread 10 ft every turn (3 minutes), and anything engulfed in the flame will take 5d10+7 fire damage every turn in the flame. 

The flame cannot be put out by any normal means, and can only be dispelled by the caster if said caster is 3rd Level and up.