Amaterasu ball

You kick a purple flaming ball at a creature or object within range. Make a ranged spell attack against the target. On a hit, the target takes 2d10 fire damage. A flammable object hit by this spell burns it even if its being worn or carried and when hit the target takes 1d4 fire damage each turn.

This spell's damage increases by 2d10 when you reach 3rd level (4d10), at the 8th level (6d10), and at the 10th level (8d10) and finally at the 12th level (10d10).