Cinder Cloud

You exhale a dense cloud of dark ash and laced with smokepowder, which billows outward in a 15-foot-radius sphere centered on a point within range. The cloud spreads around corners, and the area is heavily obscured. The cloud lasts for the duration or until it is dispersed by a moderate or stronger wind, or until it ignites.

The ash masks the smokepowder within the cloud. If open flame or fire damage passes through the cloud, it ignites in a sudden flash. When this happens, the cloud combusts, and each creature inside it must make a Dexterity saving throw. On a failed save, a creature takes 2d6 fire damage, or half as much damage on a successful one. The cloud instantly disappears.

A creature inside the cloud that can smell can detect the presence of something volatile, either through a perception check or their passive perception against a DC (all at the DM's discretion).

Using a Higher-Level Spell Slot. The damage increases by 1d6 for each spell slot level above 2. The cloud's radius increases by 5 feet for each spell slot level above 2.