Exodus 8:16-19 - Plague Three: Gnats
16 And LORD said to Moses, Say to Aaron, Stretch out thy rod, and smite the dust of the earth, that it may become lice throughout all the land of Egypt. 17 And they did so. And Aaron stretched out his hand with his rod, and smote the dust of the earth. And there were lice upon man, and upon beast; all the dust of the earth became lice throughout all the land of Egypt. 18 And the magicians did so with their enchantments to bring forth lice, but they could not. And there were lice upon man, and upon beast.
19 Then the magicians said to Pharaoh, This is the finger of God. And Pharaoh's heart was hardened, and he did not hearken to them, as LORD had spoken.