What do the two snakes on a bishop's staff mean?

The episcopal staff has the cross of Christ with two snakes and this may seem disconcerting. There are actual two explanations for this symbolism.

The staff reminds us to the brass serpent erected by Moses in the desert (Numbers 21). When the Israelites were bitten by poisonous snakes (being the sign of sin and earthly / demonic wisdom) the brass serpent that was lifted up was a type of the cross. Jesus Christ “became sin” (2 Corinthians 5:21) for us and triumphed over the poisonous and lethal power of sin. Hence, the snakes on the staff recall this story and the words of the Lord in John 3:14: “As Moses lifted up the serpent in the wilderness, even so must the Son of man be lifted up.”

Another way to consider the snakes it to see them not as symbols of false wisdom (James 3:15) but of true and holy wisdom, as in Lord’s saying (Matthew 10:16): “Behold, I send you out as sheep in the midst of wolves; so be wise as serpents and innocent as doves.”

Source: https://www.orthodoxanswers.org/orthodox-bishops-have-a-strange-staff-with-two-snakes-around-a-cross-what-does-it-mean-is-is-not-an-evil-symbol/