and it shall become a serpent.

7:10 And Moses and Aaron went in unto Pharaoh, and they did so as the
LORD had commanded: and Aaron cast down his rod before Pharaoh, and
before his servants, and it became a serpent.

7:11 Then Pharaoh also called the wise men and the sorcerers: now the
magicians of Egypt, they also did in like manner with their
enchantments.

7:12 For they cast down every man his rod, and they became serpents:
but Aaron's rod swallowed up their rods.

7:13 And he hardened Pharaoh's heart, that he hearkened not unto them;
as the LORD had said.

7:14 And the LORD said unto Moses, Pharaoh's heart is hardened, he
refuseth to let the people go.

7:15 Get thee unto Pharaoh in the morning; lo, he goeth out unto the
water; and thou shalt stand by the river's brink against he come; and
the rod which was turned to a serpent shalt thou take in thine hand.

7:16 And thou shalt say unto him, The LORD God of the Hebrews hath
sent me unto thee, saying, Let my people go, that they may serve me in
the wilderness: and, behold, hitherto thou wouldest not hear.

7:17 Thus saith the LORD, In this thou shalt know that I am the LORD:
behold, I will smite with the rod that is in mine hand upon the waters
which are in the river, and they shall be turned to blood.