Cuelebre

Historical Background
Cuélebre, or Culebre, is a giant winged serpent-dragon of the Asturian and Cantabrian  mythology, that lives in a cave, guards treasures  and keeps xanas  as prisoners. Although they are immortal, they grow old as the time goes by and their scales become thick and impenetrable, and flag wings grow in their bodies. They don't usually move, and when they do it, it is in order to eat cattle and people. One can kill the cuélebre giving him as meal a red-hot stone or a bread full of pins. Its spit it is said to turn into a magic stone which heals many diseases.