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.
Diseased people, (leprosy or any other such fear inducing disease) when traveling, will often times wear a cloak that entirely covers their body and ring a bell as they travel, used as a warning for any others to stay away. Could be used for a disguise or safe passage.