Exodus 12:12, 29-30

‘For I will pass through the land of Egypt on that night, and will strike all the firstborn in the land of Egypt, both man and beast; and against all the gods of Egypt I will execute judgment: I am the LORD.

And it came to pass at midnight that the LORD struck all the firstborn in the land of Egypt, from the firstborn of Pharaoh who sat on his throne to the firstborn of the captive who was in the dungeon, and all the firstborn of livestock. So Pharaoh rose in the night, he, all his servants, and all the Egyptians; and there was a great cry in Egypt, for there was not a house where there was not one dead.