This figure has something of the ferocity and other-worldly zeal of those Lenten preachers. I've always found this figure to be stirring, and very frightening, even more so now that he's been restored.
Remember this is the same Donatello who made that nude pretty boy bronze David. That Donatello could make something like the David and this prophet, both with conviction, is a measure of his greatness. If it wasn't for Michelangelo, Donatello would get my vote for greatest of all Renaissance sculptors.
And here it is, full force expressionism centuries before anyone ever thought of that term.
Here is the Campanile next to the Cathedral with the row of prophets, including Zuccone, just under that modern netting. They are all replicas now.