Dragon that died in the Red Waste
The dragon that died in the Red Waste is a dragon that perished in the red waste in Essos, south of Vaes Tolorro. Its large skeleton lies in the sands. It was an immense size. Whether it was wild or had been ridden is not known.
A Clash of Kings
While encamped in the abandoned city of Vaes Tolorro, Daenerys Targaryen sends her three bloodriders to explore the vicinity. Rakharo goes due south. During his travels he passes the bones of a dragon, so immense he swears to Dany that he was able to ride his horse through its great black jaws. When he returns to Vaes Tolorro he tells Daenerys Targaryen of the dragon's bones.