Exodus 9:6-9

6The next day the Lord did as he said. All the livestock of the Egyptians died, but none of the Israelites’ animals died.

7Pharaoh found out that not one of the Israelites’ animals had died. Yet, Pharaoh continued to be stubborn and would not let the people go.

8Then the Lord said to Moses and Aaron, “Take a handful of ashes from a kiln, and have Moses throw them up in the air as Pharaoh watches.

9They will become a fine dust throughout Egypt. The dust will cause boils to break into open sores on people and animals throughout Egypt.”