Ball Bearings of Levitation

This bag of 1000 magical ball bearings are enchanted with a certain type of magic. When an action is used to throw the contents of the bag, the ball bearings occupy an empty space, no bigger than 5 feet in any dimension. They also hover 15 feet off of the ground. If there is no space 15 feet off the ground, the ball bearings will go as high as they can.

When a flying creature goes through this space, it must make a dc 10 dexterity check. On a failure, the creature's flying speed will be reduced to 0, and will begin to fall, being caught up in the ball bearings. Any creature that walks through a space these ball bearings occupy will also be subjected to the same effects as ball bearings normally would.