Exodus 9:6-9

6And the Lord did this on the next day; all the livestock of the Egyptians died, but of the Israelites’ livestock not one died.

7Pharaoh sent representatives to investigate, and indeed, not even one of the livestock of Israel had died. But Pharaoh’s heart remained hard, and he did not release the people.

8Then the Lord said to Moses and Aaron, “Take handfuls of soot from a furnace, and have Moses throw it into the air while Pharaoh is watching.

9It will become fine dust over the whole land of Egypt and will cause boils to break out and fester on both people and animals in all the land of Egypt.”