Exodus 8:5, 17

Then the LORD said to Moses, “Say to Aaron, ‘Stretch out your hand with your staff over the rivers, over the streams and canals, over the pools [among the reeds], and make frogs come up on the land of Egypt.’ ”

They did so; Aaron stretched out his hand with his staff and struck the dust of the earth, and there were [biting] gnats on man and animal. All the dust of the land became gnats through all the land of Egypt.