The magicians could not stand before Moses because of the boils, for boils were on the magicians and on all the Egyptians.

It will become fine dust over the whole land of Egypt and will cause boils to break out and fester ¹  on both people and animals in all the land of Egypt.”

So they took soot from a furnace and stood before Pharaoh, Moses threw it into the air, and it caused festering boils to break out on both people and animals.