Exodus 9:9-10

and it hath become small dust over all the land of Egypt, and it hath become on man and on cattle a boil breaking forth [with] blains, in all the land of Egypt.’ And they take the soot of the furnace, and stand before Pharaoh, and Moses sprinkleth it towards the heavens, and it is a boil [with] blains, breaking forth, on man and on beast