Exodus 8:16-17

So the LORD said to Moses, “Tell Aaron, ‘Raise your staff and strike the ground. The dust will turn into swarms of gnats throughout the land of Egypt.’” So Moses and Aaron did just as the LORD had commanded them. When Aaron raised his hand and struck the ground with his staff, gnats infested the entire land, covering the Egyptians and their animals. All the dust in the land of Egypt turned into gnats.