Exod 7:9-12

9“When Pharaoh says to you, ‘Perform a wonder,’ then you shall say to Aaron, ‘Take your staff and throw it down before Pharaoh, and it will become a snake.’ ”10So Moses and Aaron went to Pharaoh and did as the Lord had commanded; Aaron threw down his staff before Pharaoh and his officials, and it became a snake.11Then Pharaoh summoned the wise men and the sorcerers; and they also, the magicians of Egypt, did the same by their secret arts.12Each one threw down his staff, and they became snakes; but Aaron's staff swallowed up theirs.