Exodus 7:10

7:10 When Moses and Aaron went to Pharaoh, they did so, just as the Lord had commanded them – Aaron threw down his staff before Pharaoh and his servants and it became a snake.

Exodus 7:15

7:15 Go to Pharaoh in the morning when he goes out to the water. Position yourself to meet him by the edge of the Nile, and take in your hand the staff that was turned into a snake.