Dust of dispersion

Dust of dispersion was a type of magical powder designed for combat situations.

Powers
A handful of this dust thrown into the air would create a translucent cloud, roughly  across in every direction. Creatures were capable of seeing into and through the cloud, though those looking through it would have their vision slightly blurred. While this was up in the air, any ranged attacks made against a creature standing inside the cloud of dust would have a lower probability of hitting. This negative probability effect lessened over time.

On average the cloud caused by a dust of dispersion would remain in the air for three minutes, though it could be dispersed quicker by moderate to strong winds. Fire-based spells could also burn away parts of it. And the dust's effects would not work underwater. Once used, dust of dispersion became inert and thus could not be reused.

Creation
Crafting a dust of dispersion required one to know the spells blur and glitterdust. And it cost around 250 gold pieces.