Note: Based on a True-life incident!
No names have been changed to protect the innocent!

Cary displayed a wicked grin as he passed by the three or four other supervisors gathered in a small knot of humanity in their cubicle area. Immediately, one after another, the they checked to see if their e-mail was open and then began to furtively flick their hands across their behinds in a manner reminiscent of a small herd of wildebeests grazing, tails flicking. Such a fine game! The implied presence of a small purple and pink plastic tail, hooked to an aft-most belt loop, was all it took to stimulate this odd behavior.

Secretly, each member of the small heard was gratified to discover he was not the recipient of the insidious posternal adornment. Greater gratification was elicited as the group spied Steve striding toward the airplane, garish plastic appendage waving in his wake.

And so it began; growing from a harmless prank to one of the most baneful diseases of modern man. (Note, that the use of 'man' is in no way intended to be sexist, as the affliction, due to EEO considerations, was at first passed exclusively from male to male by the attachment of the aforementioned adornment.)

Meanwhile, the Gear Boys snickered amongst themselves, reveling in the hilarious sight of their boss, strutting about, heedless of the pseudo-equine appendage streaming like neon flatulence from his posterior. The fun came to an end though, when either through loyalty (NOT!) or a desire to enhance his supervisor's embarrassment, one of the guys pulled on the tail, bringing Steve to an instant stop, hand flying to butt in an act of delinquent discovery.

"Damn it! Who put that there!" bellowed Steven in righteous Hawaiian indignation; as though he'd never previously done it himself.

Stewart smiled his secret smile, continuing his earnest conversation with Bob, perfectly concealing his duplicity in Steve's decoration.

Viruses, like the rest of us, have a multitude of responsibilities associated with their job descriptions. Paramount among these is mutation. A cosmic ray here, a little ultra-violet there and what was once perfectly benign becomes virulent.

It's said, the Human body is host to about fifty thousand different virus species, each in their own specialized niche. Every square in of skin has its own viral venue, all doing whatever it is viruses do when they're not causing plagues or raising warts.

*Zap*

A proton from some far-off super-nova collided with a fragment of DNA in one tiny viral visitor riding on the little metal hook attached to a certain plastic tail. Instructions were changed. "Copy this", the new fragment said, as the Code of Life was recompiled and a sequence of genetic instructions that had lain dormant for twelve million years sprang to life with insidious new additions. The mutant virus was fruitful and multiplied, and as the now-infected tail was passed from one victim to the next, the mutated critters spread. Soon everyone with a belt-loop to call his own was infected.

And so it spread; by touch (let's not go there!), or on the air, dispersed in the wake of the infected. Restaurant seats, airplane seat, toilet seats; the spread of the virus becomes a seat-of-the-pants sort of thing. Soon the virus propagated into the population at large, riding the Winds of Change around the planet.

John felt a tingle, the slightest itch in a familiar location, reflexively, his hand flicked posternally, discovering nothing. Relief. Yet… the sensation momentarily persisted. Soon it was gone, forgotten among his nervous system's background noise.

Paul swizzled in his chair, wondering how someone could have decorated him… yet nothing was there. Soon the feeling was gone.

Monty slyly looked around. Nobody was watching. His hand flicked down, finding nothing. A shrug. It passed.

An astute observer would see hundreds of these small, furtive movements over the course of a day, each lasting just a brief instant. As time past, more and more people engaged more and more frequently in what was once an extremely local avocation.

*Flick*

At the store.

*Flick*

In line at the theater.

*Flick - Flick - Flick*

At the ball game.

The disease spread. First, just a vague itch, a passing irritation. As time passed, the symptoms expanded, becoming manifest as a growing knot of tissue at the base of the spine. Doctors' offices were inundated as millions rushed to have their symptoms poked, prodded, sliced and diced. All to no avail. The disease had become a feature incorporated (literally) into the Human genome.

Within a few weeks the sites of infection began to rapidly expand as bone and cartilage grew. Pain wracked the world. Planet-wide, commerce ground to a halt as billions stayed home, nursing expanding protuberances. Temporarily, the Dark Ages returned as essential services ground to a halt. Pain had Humanity by its tail.

Doug glanced over his shoulder into the mirror, experimentally wagging the length of new pink flesh depending from his spine. Already, the first course hairs were sprouting along its length. With all of his employees at home, suffering the same affliction, his behind (ahem) schedule status was going through the roof!

Slowly, Humanity came to grips with its new appendage. The clothing industry were the first to benefit from the Change. Impromptu tailor shops sprung up on every corner, as a hundred billion garments cried out for alterations.

In less than a year, the Change was complete. In the first year after the Change, 137,912 Japanese commuters got their tails caught in train doors. Accident rates soared around the world as 'Tail Injuries' became an industrial disease.

Frank grumbled as he withdrew from a roughly square hole cut in his bathroom wall. Setting his propane torch down, he turned about to find the roll of solder lost in his toolbox. Behind him the little blue spike of flame roared.

*Foof*

"OW! Goddamn it!" Frank shouted, the new fur on the end of his tail smoldering.

Steve pranced to the airplane, his resplendent new tail swishing behind him.