By Alexandro Melchor (AlejandroM@mail.proesa.com.mx)
It has two main powers: it can change shape and assume any form: a book, a klaive, a necklace, a ring; you name it, the McGuffin can assume it; this has caused confusion about its name and has received many (Holy Grail, Excalibur, File #44271, the One Ring, etc.), however, it remains the mighty McGuffin.
The other power is that it remains lost. There's always someone looking for it somewhere, and its power is such that it can filter clues as to his whereabouts; it has many spirit servants that aid him in directing those that search for it; some of their manifestations include the Old Man in the Forest, Drunk in the Bar, Deep Throat and the infamous Dark Tall Stranger in a Tavern.
As to what it actually does is anybody's guess; no one has been able to find the McGuffin, for as soon as an object claiming to be it is found, the McGuffin's essence is transferred into another driving goal of a story.