Genesis 41:17-21

So Pharaoh said to Joseph, “In my dream, there I was, standing on the bank of the Nile;

and behold, seven cows, fat and fine-looking came up out of the Nile, and they grazed in the marsh grass.

Then behold, seven other cows came up after them, poor and very ugly and thin, such as I had never seen for ugliness in all the land of Egypt;

and the thin and ugly cows ate the first seven fat cows.

Yet when they had devoured them, it could not be detected that they had devoured them, for they were just as ugly as before. Then I awoke.