You are clearly far more well versed (excuse the pun) in matters biblical than I, but from my recollection a meteorite tens of meters across would be more likely to devastate a large area and leave a big fat crater perhaps the size of a modern town, so that's not what I had in mind.

I was thinking more of something just large enough not to burn up - just large enough to survive the atmosphere. And at the speed that would be traveling I do think it could be portrayed as a fiery serpent, especially when placed in the context of a story no doubt embellished over generations. Something tens of meters across would be thousands of times more devastating.

As for Moses and his brass serpent pole - who the hell knows? Lies? Propaganda? Science fiction? Fantasy? Someone was on acid? One of many examples that suggest to me the whole publication should never ever be read as a literal, historical non-fiction work.