Breath of Necrosis

A cloud of necrotic energy releases from your lungs and fills the air around you. Each creature (excluding the caster) within a 20-foot-radius sphere centered on you must make a Constitution saving throw. A target takes 1d10 + spell modifier necrotic damage on a failed save, or half as much damage on a successful one.

The cloud spreads around corners, and causes any nonmagical plant-life that isn't a creature to wither and die

At Higher Levels. When you cast this spell using a spell slot of 2nd level or higher, the damage increases by 1d10 for each slot level above 1st.