The serpent is the symbol of divinity and royalty. It is also a symbol of Hadit, invoked upon them.
For the images in this and the next verse see the Stele of Revealing, to which they allude.
The Serpent is the Uraeus, with the powers of Life and Death, wise, ecstatic, immortal; winged and hooded, that he may go as a god swiftly and silently. It refers in this place especially to Hadit.