Toxic Breath

You exhale a cloud of misty vapor in a 30-foot cloud in front of you. Each creature in the cone must make a Constitution saving throw. On a failure, a creature takes 8d6 poison damage, and it is poisoned until the start of your next turn. While poisoned in this way, its speed is reduced by half. On a success, a creature takes half damage and is not poisoned.
At Higher Levels. When you cast this spell using a spell slot of 4th level or higher, the damage dealt increases by 1d6 for each spell level above 3rd.