What does Ezekiel 29:3 mean?

Tell him, ‘This is what the Lord God says: I am against you, Pharaoh, king of Egypt, you great monster lying in the Nile, who says, “The Nile belongs to me; I made it myself.”’ Ezekiel 29:3 - Modern Text Bible

(God confronts Pharaoh’s arrogance, picturing him as a giant crocodile claiming the Nile as his own creation.)