Brewfernne's Septic Spitfire

A stream of sickly green fire sprays from your mouth toward a target within range. The target must make a Dexterity saving throw. On a failed Dexterity saving throw, the target takes 6d6 fire damage and must make a Constitution saving throw. On a failure, the target is Poisoned  for one minute. The target repeats the Constitution saving throw at the end of each turn. On the start of every turn that it is poisoned it takes 2d6 poison damage. On a successful Dexterity save, the target takes half fire damage.

At Higher Levels. When you cast this spell using a spell slot of 4th level or higher, the fire damage increases by 1d6.