Dragon of the Darkness Flame

A black flame erupts from your arm in the shape of a dragon. The area of the dragon consists of up to twenty 5-foot cubes, which you can arrange as you wish. The first cube must be centered on yourself and each cube must have at least one face adjacent to the face of another cube. Each creature in the area must make a Dexterity saving throw. It takes 4d12 fire damage on a failed save, or half as much damage on a successful one.

Since the dragon is made from the unique darkness flame, creatures with fire immunity instead take half damage while those with resistance take full damage.

The fire damages objects in the area and ignites flammable objects that aren't being worn or carried. If you choose, plant life in the area is unaffected by this spell.