Aether Ignition

Channeling the unseen energies of the plane itself. Choose a target within 60 feet and ignite it with invisible flame, dealing 8d6 fire damage. On each of its turns, it can make a intelligence saving throw to attempt to discern whether it can perceive the flame on its body.  On its turn, it can use its action to attempt to remove the flame by dousing itself in an amount of water capable of fully submerging it. 

When you cast this spell using a spell slot of 4th level or higher, the damage increases by 1d6 for each slot level above 3rd.