Vacuum Aura

Wind whips into a frenzy creating an airtight 20 foot sphere around you. While the spell is active, your movement is halved and the sphere remains centered on you. Each creature (except for you) that starts it's turn in the sphere must make a constitution saving throw. A target takes 4d6 bludgeoning damage on a failed save, or half as much damage on a successful one. A target that has failed it's saving throw is unable to breathe or cast spells that require verbal components.

At Higher Levels: When you cast this spell using a spell slot of 4th or higher, the damage increases by 1d6 for each slot above 3rd.