Carbuncle
According to medieval bestiaries, the carbuncle was a stone obtained from the forehead of dragons that, once held up to the sun, shone like a burning coal.
But in the myths of southern Chile, the carbunclo is a legendary quadruped the size of a cat that bears a luminous chin beneath its jaw. It is considered the guardian of treasures and precious metals, with which it becomes confused through the effect of metamorphosis.
In Peru, the carbuncle is an animal somewhat larger than a fox that carries on its forehead a light that turns on and off at will.