Kalraka Dzeik is a sentient lightning storm with a following of cultists. It has much in common with a natural disaster or a plague; it starts at a single point but spreads like wildfire if given the chance. It is capable of terrible destruction, and will take heroic effort to stop, if it can be stopped at all.
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.