Exodus 9:9-11

9It will become fine dust over all the land of Egypt, and will become boils erupting with sores on both men and animals throughout all the land.”

10So they took soot from the furnace and stood before Pharaoh. When Moses threw it heavenward, it became boils erupting with sores on both men and animals.

11Moreover, the magicians could not stand before Moses because of the boils, because they were on the magicians, as on all the Egyptians.