Exodus 9:8-10

8Then the Lord said to Moses and Aaron, “Take handfuls of soot from the brick kiln, and let Moses throw it toward the sky in the sight of Pharaoh.

9It will become fine dust over the entire land of Egypt, and it will become boils breaking out in sores on man and animal in all the land [occupied by the Egyptians].”

10So they took soot from the kiln, and stood before Pharaoh; and Moses threw it toward the sky, and it became boils erupting in sores on man and animal.