Exodus 7:10 – 12
New International Version (NIV)
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.
From BibleGateway.com: http://www.biblegateway.com/passage/?search=search=Exodus+7.10-12&version=NIV