Avarone's Conflagrant Arm

Your arm bursts into flames. Choose to use all the energy at once or save it and concentrate on its use. When you using the energy all at once a jet of flame shoots forth from the your outstretched arm, each creature in a 60 foot line must make a Dexterity saving throw to avoid the jet taking 12d4 + 12 fire damage on a failed save. This spell, also known as Trollbane, will set alight any combustible material it strikes that is not held or carried on a creature.

If you choose to control the energy over an extended period of time, then as an action you can spout a jet of flame. Make a ranged spell attack to strike one creature you can see within 60ft for 12d4+12 fire damage.  While your arm is still ablaze, and if you have not used your action to spout a jet of flame you may perform other actions. As a reaction you may make a melee spell attack against a creature that has struck you this turn for 12d4 + 12 fire damage. You have resistance to fire for the spell duration.

At Higher Levels. When you cast this spell using a spell slot of 7th level or higher, the damage is increased by 1d4+1 for each slot level above 6th.