Wand of Zero-Effect
This wand is plain wood, without ornament or artifice. It is an imperfect cylinder which unless detected for magic would appear to be just piece of kindling or a stick. When waved in a certain pattern and commanded to shoot forth fire and lightning the wand does nothing. When struck against the body of a dead companion the wand does nothing. When dipped in sour milk the wand gets smelly. Indeed, despite the impressive magical aura the wand has, it seems even with the best of divination magics and upon consultation with the gods themselves, to do absolutely nothing whatsoever. Or at least nothing that a normal stick wouldn’t do.
Every fifty years or so the wand makes a reappearance and mages pour over it trying to discover the command word that will unlock its truly fabulous powers. For the one who discovers that command word will become a king among wizards, with powers unto those possessed by the gods themselves, able to turn light into gold and to hold the sun itself between their tightly clenched buttocks! Then do the dance of the three bananas upon the faces of their enemies and no-one will ever be able to stop them! Ahahahahaha!
Or so they think.
Because the wand does have one single effect that no-one has ever guessed. It drives wizards mad. Any spell caster who possesses this wand will gradually feel compelled to devote more of his time to studying it. Every divination spell that is cast upon the wand results in a reduction of 1 to the wizard’s wisdom score. This fact should be kept secret by the DM, as at first the wizard himself doesn’t notice a thing. Upon losing one third of his wisdom the wizard realises within a few days that something is wrong with him and that he is going mad, but he may not attribute that to the wand – and even if he does it may make him even more keen to know what it does. If his wisdom reaches zero he goes permanently and completely insane; mad as a loon; nutty as a squirrel’s larder. Providing the wizard doesn’t drop to zero wisdom, his wisdom returns at a rate of 1 point per week of seclusion and rest.
The wand is obviously the product of some god (probably Faceless Roon, the god of secrets) and resists all attempts to destroy it, despite its commonplace appearance. A wizard will usually start losing his wisdom upon first discovering the treasure horde the wand is in (its previous owner perhaps tried to slay a dragon by saying “Ni” to it) and casting the obligatory detect magic upon it. Non-wizards are not affected by the wand, to them it appears to be just a stick.
(This item is from the world of Saas)