Paradox Cloud
From Tardis Wiki, the free Doctor Who reference
The Paradox Cloud was a menacing purple thunderstorm cloud that appeared in the sky across time and space, wrecking havoc on everything it came into contact with, changing them. It was created by the Master using the Paradox Engine.
The effects of the Paradox Cloud could be negated by usage of Paradox Dust. (GAME: Hidden Mysteries)