n°2 / Exodus 8 :

22And I will sever in that day the land of Goshen, in which my people dwell, that no swarms of flies shall be there ; to the end thou mayest know that I am the LORD in the midst of the earth.
23And I will put a division between my people and thy people : to morrow shall this sign be.
24And the LORD did so ; and there came a grievous swarm of flies into the house of Pharaoh, and into his servants’ houses, and into all the land of Egypt : the land was corrupted by reason of the swarm of flies.