Old Wildfire

At 2nd level, you gain the ability to create flames around you.

As an action, you can expend one use of your Wild Shape feature to ignite a raging wildfire. When you do so, you gain a number of temporary hit points equal to your druid level × 5, which last for 10 minutes. While you have these temporary hit points, you have resistance to fire damage, your melee weapon attacks deal additional fire damage equal to your Wisdom modifier, and you can see through areas that are heavily obscured by smoke.

Choose a point you can see within 60 feet of you. A 5-foot sphere of flames appears centered on that point, and burns while you have these temporary hit points. When a creature other than you enters the area for the first time on a turn or starts its turn there, it must succeed on a Constitution saving throw against your druid spell save DC or take 1d6 fire damage. Foliage and flammable objects that aren't being worn or carried within the area are set ablaze. For every gallon of water splashed on the wildfire, you take 1 cold damage.

The damage and radius of this wildfire increases as you gain levels in this class, to 2d6 and up to a 10-foot-radius at 6th level, 3d6 and up to a 15-foot-radius at 10th level, and 4d6 and up to a 20-foot-radius at 14th level.

As a bonus action on your turn, you can extend your wildfire to a 5-foot cube adjacent to it, or choose a 5-foot cube within your Wildfire to extinguish. If you cast a spell that deals fire or lightning damage on a turn, you can extend or extinguish the wildfire by an additional number of 5-foot cubes equal to the spell's level.

When your wildfire ends, any soil burned by it becomes rich and fertile, and will begin showing signs of plant growth in 1d10 days, if other conditions allow for it.