Cinder Smoke

You create a 20-foot-radius Sphere of smoke centered on a point within range. The area within the sphere is Heavily Obscured. The smoke lasts for the spell's duration or until a strong wind (such as one created by Gust of Wind disperses it.

A creature that enters the smoke for the first time on its turn, or that starts its turn there, must make a Constitution saving throw. On a failed save, a creature begins Burning and must hold its breath or begin Suffocating. A creature that starts Burning this way takes 2d4 Fire damage each turn instead of the normal damage. A creature with Resistance or Immunity to Fire damage, or that does not need to breathe, is immune to the suffocation caused by this spell. Moving out of the smoke allows a creature to breathe normally again.

On a successful save, a creature does not start Burning and suffers no additional effects.

Using a Higher-Level Spell Slot. When you cast this spell using a level 4+ spell slot, the Burning damage increases by 2d4 for each slot level above 3.