One of the things you always carry around, and never give it a second look. But even a second look would not help to reveal this one.
Pandora would have opened this one, too.
The everful horn of a vengeful bull-like creature who wants it back…
It is a magical bug, that will allow the owner to hear what is said in the immediate vicinity of the “bug.”
This tome may give you the information you seek, though you may not be happy reading it. Not really cursed, but gives the information in such a way that many readers despaired before finding the right knowledge.
You receive a vision of a rooftop "somewhere close by", where a rare moss grows; in the vision, you know the moss is suitable for greatly enhancing the effects of certain types of potions. Now go and find that rooftop. Don't fall off. (Of course, rooftop runners *will* be taken for miscreants by the local City Watch....)