the bronze snake was called Nehushtan. the full story is that God sent poisonous snakes among the Israelites for speaking against Him and Moses. If they were bitten, they had to look at the statue to be healed. After Israel was fully established as a nation, Nehushtan began to be worshipped in his own right. Eventually King Hezekiah realized reverence of the artifact had become full blown idolatry, and he ordered the destruction of all Nehushtan statues.