Papyrus

Anything you write on this paper will come true. There's no catch, no twist; it just works. If there’s a drawback, I suppose it’s only that whatever you obtain, the thrill will soon fade, leaving you wanting even more. Thus, I—a simple piece of stationery—will quickly become the most valuable item you possess. Far more prized than whatever riches you request, concubines you gain, peace or war or weapons you demand, mansions or yachts or Jetstreams or properties you own, laws of nature you alter. Anyway, you killed my previous owner to get me, so enjoy! What’s your first wish?