Exodus 9:7-11

And Pharaoh sent men, and they learned that, behold, not even one of the livestock of Israel was dead. But the heart of Pharaoh was hardened, and he did not let the people go. The Plague of Boils

Then the Lord said to Moses and Aaron, “Take for yourselves handfuls of soot from a kiln, and Moses shall toss it toward the sky in the sight of Pharaoh.

Then it will become fine dust over all the land of Egypt, and will turn into boils breaking out with sores on every person and animal through all the land of Egypt.”

So they took soot from a kiln, and stood before Pharaoh; and Moses tossed it toward the sky, and it became boils breaking out with sores on every person and animal.

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