In the English edition of "The Adventures of Huckleberry Finn" (at least the version available on gutenberg.org), this sentence appears:
"It's the brazen serpent in the wilderness!
The Spanish translation found elsewhere is:
«¡Es la serpiente de bronce del desierto!
If I'm not mistaken, a reverse translation would be, "It is the bronze serpent of the desert!"
Why is "brazen" translated as "bronze"?
Note: in actuality, the serpent on the pole (which was made when the Israelites were wandering in the desert) was said to be of copper, not bronze (see this for the details).