Exodus 9:9-11

9It will become fine dust over the entire land of Egypt. It will become festering boils on people and animals throughout the land of Egypt.”

10So they took furnace soot and stood before Pharaoh. Moses threw it toward heaven, and it became festering boils on people and animals.

11The magicians could not stand before Moses because of the boils, for the boils were on the magicians as well as on all the Egyptians.