The Wyvern Orb

The Wyvern Orb is an item of great enchantment, made by Mithroaz the Great in the era before The Unforging. Obsessed with drakes and dragons, the mage sought to fashion an item that would attract and control the poisonous creatures found making their nests throughout the Dragonspire Mountains. Through the item, he was able to study the creatures' habits and natural fighting techniques, as well as harness their poison and make a hefty profit from the endeavor by selling it as a rare ingredient in the creation of magical items and potions. If poisons were made from it, the mage chose to turn a blind eye, although he himself claimed to have never sold it to anyone who willingly would use it for such dark ends. More than one noble of the time period fell to what was believed to be wyvern poison, however.
The Wyvern Orb is a round sphere of dark magical glass that churns with blue smoke or clouds once someone takes a minute or two to concentrate on the dark and swirling blue clouds in the item. When activated by the user, wyverns within ten miles find the item irresistible and will know its location. They will actively seek out the orb. This is where the true power of the orb comes into being, as the user becomes practically invisible to the creatures that have heeded the Orb's call. Wyverns will have a range of emotions triggered by the orb, from irritation and anger to believing that it it fighting over a mate or protecting a new brood of hatchlings.
Wyverns must succeed in an Intelligence check DC 16 at a -2 penalty to notice the presence of the Orb's wielder. If a wyvern notices the wielder, it will be enraged and will attack immediately with a +2 to all attack rolls made against the Orb's master. Fortunately, the Orb confers immunity to wyvern poison as long as it remains in the physical possession of the mage. The Orb does not confer immunity to physical damage.
Over the centuries, the magic in the Orb has changed and now continually leaks out in small "pulses" such that any wyvern within 10 miles has a 10% chance of noticing the Orb even if the mage is not actively using it. This magical effect will not be immediately noticed unless the mage has had it in his or her possession for a period of at least 24 hours. After this time, a mage making a successful Arcana check, DC 14, will notice the power instability.