Aaron's rod became a snake
Aaron's rod became a snake and then turned back to a rod under God's Command in front of the Pharaoh.
This event happened before the Plague of Blood happened, which was the first plague out of ten plagues.
Moses was eighty years old and Aaron was eighty three years old when this happened.
though out the time with the Pharaoh of Egypt God spoke to Moses who talked to Aaron who then told the Pharaoh.
Aaron's Staff Becomes a Snake
8 The LORD said to Moses and Aaron, 9 "When Pharaoh says to you, ‘Perform a miracle,' then say to Aaron, ‘Take your staff and throw it down before Pharaoh,' and it will become a snake."
10 So Moses and Aaron went to Pharaoh and did just as the LORD commanded. Aaron threw his staff down in front of Pharaoh and his officials, and it became a snake. 11 Pharaoh then summoned wise men and sorcerers, and the Egyptian magicians also did the same things by their secret arts: 12 Each one threw down his staff and it became a snake. But Aaron's staff swallowed up their staffs. 13 Yet Pharaoh's heart became hard and he would not listen to them, just as the LORD had said.