This object is capable of providing potent portents, prophecies and predictions. The Prophecy Urn is three feet tall. It's bulbous, two-foot wide base narrows to a slender neck culminating in a flaring mouth. A pair of looped handles of polished brass flank the Urn's neck. The Urn is made from some black metal, smooth and polished to a glossy sheen, but this material is only visible within the object's neck. The exterior of the Urn is sheathed in a leather and fur casing made from the preserved facial skins of dozens of creatures, both natural and unnatural. Specimens include a sad-looking human, a snarling badger, a tiny praying mantis, a haughty cat, a twisted imp, a scaly lizardman, and many more. Each face is a fine example of the taxidermist's art, eyes replaced with flecks of colored stone or glass, teeth carefully carved from ivory or stone, features given form by carefully placed beneath the skin. The Urn is both large and heavy, moving it requires the efforts of two strong men.
The Urn radiates Superb summoning magic. A Great test of divination magic will reveal the basic operations of the device, with a Superb test of divination or magical lore required to discern the specific command words needed.
To activate the Urn an offering of some sort must be placed within and the proper command word spoken. This brief rite causes the Urn to summon a supernatural being and bind it to one of its many faces. If the Urn's owner knows the true name of a supernatural being, they may combine this with the Urn's command word to summon the named being. The being so summoned may use the head to see, hear, and speak, but no other actions are possible. The binding compels it to answer three questions to the best of its abilities. Once these questions have been asked, or half an hour passes, the being is freed from its compulsion and returned to its place of origin.
The exact nature of the being summoned is determined by the type and quality of the sacrifice offered. An offering of fresh meat might summon a hungry animal spirit, earth might call forth a patient tree spirit, gems a potent earth elemental, and blood a tricky demon. Creatures summoned will only answer questions to the best of their knowledge. Quizzing a nature spirit about the inner workings of the demonic realm would be fruitless for example, but asking it about a nearby forest might provide detailed information. The GM should determine the summoned creature's type and available knowledge based on their setting.
PS - I'll eventually get around to adding a page that outlines the system I use for quasi-system-free descriptions. Until then, take a look at this article from the RPG Dumping Ground, which covers the ground.