Air Mine

Without any verbal or visual requirements, you may create a 5ft sphere within a 30ft radius of yourself of air. After casting, it takes 1 turn for the mine to actually work. (If this is sped up by any means, it becomes instant.) This lasts 30 seconds or until something interacts with it in any way, including detect magic. If an item hits the sphere directly, it flies 60ft in the direction of the sphere it was hit. Items fly at 30 ft/s, however you DM may slow the item down as they see fit for weight. For every foot, reduce the knockback by 20ft per foot until 3ft away, then feel a light gust until 15 ft. This can interact with any item or thing, so you can throw a sword at it and have it hit you enemy in the back. The only way this spell can deal damage is if something coming off the mine hits a person, it cannot deal damage directly. Air Mine must be cast where only gaseous forms exist, it cannot interact with solids or liquids until it has taken effect.