The following magical item was originally inspired by +JD Clement and the folks who play in his Saturday night Swords & Wizardry game as well as my old fashioned upbringing as a Polish-American. For some reason, folks don't seem to like accordion music these days...
"Why, I heard a Madness Bellows once, on the occasion of 74th Emperor of Ozgul's 74th birthday, and it was enchanting. I believe that that was precisely the problem, though, as the resulting mania drove the Emperor to murder and then consume all the heirs likely to become the 75th Emperor of Ozgul in front of all his guests who might have been appalled had they not been engaged in sating their own deplorable, cannibalistic urges. Me? Oh no, by that time, I was far too intoxicated for murder. I just sat back and watched the show." - Master Guang-Yuan Jo
In a world where the Metal Gods hold real and lasting sway, it should come as little surprise to the outside observer that musical instruments of all shapes and sizes are commonly imbued with special significance, mysterious magics and even cosmic powers. Many a long quest have been launched by great musicians in search of one of the fabled Seventeen Lutes of Ottia of Thrax or the legendary brass double-pipes of Nacoll the Fiend, but only the rarest, most insane of bards ever dare to try to locate a set of Madness Bellows.
Semien Orwolicz was a master bard in his own right when he turned away from conventional music and began to seek out what he (and prior mathematician-philosophers) called the "music of the spheres," the sounds that the universe made in the gulf of space between planets and even, he hoped, between the moments of time itself. Semien's research and theories created many new instruments, most of which were largely useless and impractical, but the final breakthrough which rended his psyche and drove him mad also created his final instrumental invention, the Madness Bellows.
The Madness Bellows affixes a series of reeds - not unlike those common in woodwind instruments - to either end of a bellows-like device, so that, when reeds are triggered and the bellows is pumped, sound is generated. Most Madness Bellows feature reeds that play individual notes (for usually around 2 or 3 octaves) in the right hand and ones that play bass chords in the left (between 12 and 120 buttons for the left hand, varying from instrument to instrument). The sound produced, using both bass chords and higher-register melodic notes, is unlike the sound produced by other instruments and, instead, produces a rich, broad sound pallette similar to that of a small chamber orchestra or sophisticated organ.
The "madness" part of the Madness Bellows comes in subtly at first. There is a degree of cognitive dissonance that the human mind experiences when a single instrument is capable of making a richness of tone normally reserved for two, three or even more musicians. The ability to play both the root chords of a musical composition as well as the melodic line out of the same instrument forces the minds of some observers to spend too much mental effort reconciling the two halves of the same whole, and thus they remain safe from the instrument's more insidious effects. For truly, when operated by a master, the Madness Bellows opens the minds of its spectators to precisely what Semien had hoped and causes them, through music, to witness the enormity of the void of space and time... and what lives there.
To use a Madness Bellows, the would-be musician makes a Personality check versus a DC 10 (remember that, without experience, such a check should be made with a d10 rather than a d20 until a degree of proficiency in the instrument has been reached). Any failing check results in an annoying cacophony that instantly makes the musician the target of ire of any who can hear him (often leading to intra-party arguments and making the musician the target of enemies). A success, however, means that all who can hear the music must make a Will save (DC equal to the Personality check result). Creatures with less than 6 Intelligence who fail their Will save are stunned by the music, unable to sort out how its able to make so many different sounds at the same time (similar to paralysis). Creatures with an Intelligence of 6 or more (but not yet cosmic-level intelligences), however, experience a direct connection with the insignificance of mortal life when compared to the impossible hugeness of infinity, catching the merest glimpses of the true nature of time and space and perhaps even of its master, the dread Outer God, Azathoth, before going at least temporarily mad. The effects of both the catatonia and the temporary madness last for 1d4!+Per turns (that's 1d4 exploding plus Personality, if you were wondering).
Fumbles on each of these rolls are exceptionally bad things. Should the user roll a "1" on his skill check, he suffers the same fate as a failed Will save against his appropriate Intelligence. Rolling a "1" on the Will save, should the character's Int be less than 6 means permanent catatonia (which may be healed through typical means such as Remove curse); otherwise the madness experienced is not temporary, but permanent.
If the user of the Madness Bellows is a wizard or elf bonded to a patron that prizes insanity or to Azathoth himself, me may add his caster level to his performance check (making the roll d20+Per+CL vs DC 10).