Meraxes was the silver-scaled, golden-eyed dragon of Queen Rhaenys Targaryen, large enough that a horse could ride down her gullet. She was the third of the three dragons of the Conquest, and on the Field of Fire she and Vhagar burned the host of Mern Gardener and Loren Lannister into a smoking ruin.
After the Conquest Aegon turned his attention to Dorne, the one kingdom he had not subdued. The Dornish refused open battle, melting into the deep desert and trusting to ambush; for years dragons burned Dornish towers to no lasting end. In 10 AC, as Rhaenys assaulted the Hellholt, a scorpion bolt from the castle struck Meraxes through the eye. Dragon and rider fell together from the sky. Neither rose again, and Aegon ended the First Dornish War soon after.