This list of mythical creatures that begin with this letter and I am constantly gathering information from each continent, and is continually being updated.
Cuelebre (Asturian and Cantabrian)
Cuelebre (Asturian) or Culebre (Cantabrian), is a giant winged serpent-dragon of the Asturian and Cantabrian mythology, that lives in a cave, guards treasures and keeps anjanas (also known as xanas) as prisoners. Although they are immortal, the cuélebre age, and their scales become thick and impenetrable, and bat wings grow in their bodies.
They must eventually flee Asturias and fly to the Mar Cuajada, a paradise located beyond the sea. They do not usually move, but when they do it, it is in order to eat cattle and people. One could kill the cuélebre by giving them a red-hot stone or a bread full of pins to consume. Its spit is said to turn into a magic stone, which heals many diseases.