I remember a fantasy book in which one of the elements was magic hedgehogs, only they called them “urchins.” There were ones with gold spines and ones with black spines, and the black ones' spines were poisonous. Unfortunately, I can't remember anything else about the book, or if I can I've forgotten it was the same book. I’m vague about the date; it could be any time between 1990s and now — and that's assuming it wasn't second-hand at the time, though I rather think it wasn't. Does anybody here happen to recognise these hedgehogs?
Edited to add: There might possibly have been a unicorn? But I may be mixing it up with a different book entirely there.