How does Paul address the Galatians at the start of Galatians 3?

Answer: O foolish Galatians!

"O foolish Galatians! Who has bewitched you?" Paul reminds them that Christ was clearly portrayed as crucified before their eyes.

“O foolish Galatians! Who has bewitched you? Before your very eyes Jesus Christ was clearly portrayed as crucified.”— Galatians 3:1 (BSB)