Five crowns were created to bind together five regions into a single powerful kingdom, while a sixth crown was created to control the five.
Pity that someone went and destroyed the Crown of Crowns
What if some crazy wizard created an artifact that empowered rodents that touched it with one random supernatural power? Preferly right out of the pages of your favorite four-color. (But only one power!) This item does not convey any sort of intelligence boost.