Wyvern

Y Draig Aur, a flag with a wyvern that was carried by Owain Glyndŵr, Prince of Wales.^[1]

A wyvern (/ˈwaɪvərn/ WY-vərn, sometimes spelled wivern) is a legendary winged dragon that has two legs.^[2]

Wyvern Media

Wessex is often, in modern times, symbolised by a wyvern or dragon. While there is little to no evidence that it explicitly identified Wessex at the time of the kingdom, the association was popularised in the 19th century. The above flag was created by William Crampton, an advocate for English regional flags, in 1974.
A wyvern from a fourteenth-century manuscript in the National Library of Wales, Aberystwyth: this example has a second head at the end of its tail.
A carved wyvern on the choir stalls of Chester Cathedral in Cheshire, England, c. 1380
Wyverns supporting the arms of John Churchill, 1st Duke of Marlborough
Arms of Sophie, Countess of Wessex
A wyvern fighting with a wolf, relief, Trento Cathedral, Italy
Arms of Midland Railway at Derby station, bearing in crest a wyvern sans legs
Wyverns as supporters in the coat of arms of the Portuguese House of Braganza
43rd (Wessex) Infantry Division insignia (World War II)