Exodus 8:21

8:21 If you do not release my people, then I am going to send swarms of flies on you and on your servants and on your people and in your houses. The houses of the Egyptians will be full of flies, and even the ground they stand on.

Exodus 8:24

8:24 The Lord did so; a thick swarm of flies came into Pharaoh’s house and into the houses of his servants, and throughout the whole land of Egypt the land was ruined because of the swarms of flies.