The Gas Dancers of Zirna

On the planet Zirna some of the inhabitants are from time to time taken posession of by an alien being. It is not really a dangerous situation, as they do not take to hurting themselves or others. They just start behaving differently enough that others may be inclined to say of such an individual "That's just not like her" or "He's not himself today". Someone generally known to be polite and generous of spirit may be heard saying unkind things about a co-worker behind their back, or a normally shy individual may suddenly be given to playing practical jokes that no one else finds the least bit amusing. It is then that the shaman is brought in to perform an exorcism, to the accompaniment of  ceremonial music.

The exorcism can take anywhere from three hours to three days, no telling, but the music is hot and there isn't much happening on Zirna a lot of the time. So people gather in groups, bring out the elders, let the kids run loose, and enjoy picnic lunches while the shaman goes about his work. The ritual itself is entertainment in its own right, but what all the spectators are really hoping for is to be present at its denouement, when things get really interesting.

For you see, when the demon leaves the body it is expelled with an enormous belch, the gas of which is visible, being transparent but with a light greenish hue and slightly luminescent. It gathers over the head of the delivered Zirnian, taking on a quasi-humanoid shape and emanates a gentle and quite pleasant aroma, like that of deli-style Kosher dill pickles.

The demon then invariably proceeds to perform what appears to be some sort of dance, to  the strident tones of the shaman's music, undulating gently and gracefully, not unlike a jellyfish. The mysterious, magical dance seldom lasts more than a minute, often quite less, and there is no predicting the moment the demon will choose or be compelled to exit its host, so to experience its strange beauty one must be on-site, watching and waiting with some diligence. Upon completion of its gaseous manifestation, the demon dancer disperses into the atmosphere and disappears.

The Zirnians have not yet arrived at a concensus as to whether the demon's dance is meant to frighten or amuse. But it seems harmless enough, and most of them find it thoroughly delightful.

The simple fact of the matter is that the posession of a Zirnian is the only outlet through which a Gas Dancer can manifest itself. Like some terrestrial insects that live only long enough to mate and then immediately die, these dancing demons exist to do this one and only thing. It is their identity, their art, their job, and the doing of it is its own and entire reward. But they need an intermediary, and a medium through which to express themselves. The Zirnian's gas just happens to be the medium of choice for the dancing demons.

For the Zirnians' part, what they especially appreciate about this phenomenon is that they can't buy it or own it, market, advertise, or promote it. There is no way to induce it, anticipate its coming, or guess the moment of its realization. They are impotent to control it or bend it to their wishes; it just happens. And they delight in this as a kind of beauty all its own, precious, and comparable to few other things, like real love, and earthquakes.