Venomous Blast

You unleash a concentrated burst of toxic energy, sending a wave of venomous gas in a direction you choose within range. The gas spreads out in a 30-foot cone originating from you. Each creature in the cone must make a Constitution saving throw. On a failed save, a creature takes 5d8 poison damage and becomes poisoned until the end of its next turn. On a successful save, it takes half as much damage and isn't poisoned.

At Higher Levels. When you cast this spell using a spell slot of 4th level or higher, the damage increases by 1d8