Wave of poison

A wave of damp green sulfurous mist rapidly expands outward to a 40 foot circle around the caster choking and corrupting everything within. Any creature aside from the caster within the circle as it is cast or who end their turn in the circle must make a Constitution saving throw. On a failed saving throw a creature takes 2d12 necrotic damage and becomes poisoned, on a successful save the creature takes no damage and is not poisoned.