Din's Fire

You thrust your palm into the ground, and from that point a sphere of magical flame arises and rapidly expands outward. This fire does not harm you or any creatures you designate, but incinerates all other creatures and objects in a 15 foot radius centered on you.

Any affected target makes a Dexterity saving throw. On a failed save, the target takes 3d8 fire damage, and is ignited for the duration. While ignited by this spell, a creature takes 1d8 fire damage at the end of each of its turns. An ignited creature can use its action to extinguish the flames and end this condition.

On a successful save, a target takes half as much damage and isn't ignited.