Perseus doesn't look at his trophy because Medusa's stare would turn him to stone. Maybe that's why his stance is that of a victor, but he keeps his head down as if he's been defeated. But why is he holding Medusa's head up for us to see? It's as if Cellini wants us to be dead still. But not petrified by Medusa's horror, but hypnotised by his statue's beauty. Simply spellbinding.