Mysterious Animal

"In sixteenth-century South America, the name [Carbuncle, from the Latin carbunculus , ‘a little coal’] was given by the Spanish conquistadors to a mysterious animal - mysterious because nobody ever saw it well enough to know whether it was a bird or a mammal, whether it had feathers or fur. The poet-priest Martín del Barco Centenera, who claims to have seen it in Paraguay, describes it in his Argentina (1602) only as ‘a smallish animal, with a shining mirror on its head, like a glowing coal . . .’ 

Another conquistador, Gonzalo Fernández del Oviedo, associates this mirror or light shining out of the darkness - two of which he glimpsed in the Strait of Magellan - with the precious stone that dragons were thought to have hidden in their brain. He took his knowledge from Isidore of Seville, who wrote in his Etymologies: 'It is taken from the dragon’s brain but does not harden into a gem unless the head is cut from the living beast; wizards, for this reason, cut the heads from sleeping dragons. Men bold enough to venture into dragon lairs scatter grain that has been doctored to make these beasts drowsy, and when they have fallen asleep their heads are struck off and the gems plucked out.'

Here we are reminded of Shakespeare’s toad (As You Like It, II, i), which, though ‘ugly and venomous, Wears yet a precious jewel in his head . . .’  Possession of the Carbuncle’s jewel offered fortune and luck. Barco Centenera underwent many hardships hunting the reaches of Paraguayan rivers and jungles for the elusive creature; he never found it. Down to this day we know nothing more about the beast and its secret head stone."

- Jorge Luis Borges (1899 - 1986)
The Book of Imaginary Beings