Ancalagon the Black.
Ancalagon were a winged Dragon, he was the Lord of the winged Dragons. Morgoth bred Ancalagon and let him loose in the last battle of Beleriand. In "The War of Wrath" it is said that Eärendil slew him. In his fall from the sky, Ancalagon broke Thangorodrim.
Related Links.: Battles.: War of Wrath. Encyc.: Ancalagon.