Ammonia spray

 blow on the component and utter the incantation. Pointing the component at a designated target area. The component instantly excretes a 20 feet cube of ammonia vapor. All targets in the area must make a DEX save or be coated in the spray. If failed they take 1d6 poison damage, if an open flame enters the cube or touches a coated target within 3 turns of the casting, the cloud or coated target bursts into flames taking 3d6 fire damage.

(clarification notes)
if a creature coated in the spay is hit with fire damage they do not make a second save.
if the creature is standing in the cloud but is not coated they must make a second DEX save to half the damage of the spray igniting
if the attack that lights the spray has a dex save use that one save for both the attack and the spray igniting.