(FORTUNE Magazine) – This is to relate the sad story of a certain Dr. Henry Jekyll, who has become notorious because of the depredations he has wrought upon the civilized economy. Perhaps in telling it I will find some peace and be able once again to sleep at night with confidence in my portfolio.

When I first knew Dr. Jekyll, he was a respected physician with an interest in the stock market. It was his contention that with proper research and study of the events of the day, profit could reliably be wrested from the arms of commerce. To this theory he dedicated his investigations.

Throughout the 1980s the scientist worked in his laboratory, studying the consolidation of industries and generally benefiting in a small way from the greed and brutality of the acquisition environment at that time. You should have seen him then! In his pinstriped suit and yellow polka-dot power tie, hair greased back to reveal a wicked widow's peak, he was the picture of rational avarice.

It was in the 1990s that his inquiries drew him into deeper waters. I recall visiting him one evening in his lair downtown. It was a dark and stormy night. There was lightning and everything. I found him in the midst of a pile of tatty prospecti, his hair disordered and a demented look in his eye. "I have found the secret of wealth beyond your wildest dreams!" he cackled, brandishing an offering from a company that promised to come to your house and wash the dog.

"Look at yourself, man!" I said to him then. "You are going beyond the bounds of nature!" He chuckled amiably and thrust me from his residence.

It was then, in the late portion of that tumultuous decade, that a vicious, cringing, drooling homunculus began frequenting the establishments that serve the capitalist classes. Dressed in ill-fitting, inappropriately casual garb and brandishing a laptop he plugged in at seedy Internet cafes, this troll inspired fear and disgust in all who saw him. Where others respected the stately nature of the market, he traded with no regard for rationality or research, buffeted by little but emotion and rumor. Where my friend Jekyll, even at his worst, was all Mind, this dark creature was all Gut, and he smelled like fear.

"Begone, foul creature!" I yelled at him one evening as I saw him hanging around the edges of a discussion of hedge funds at a local tavern.

"Grrrr," he said, scurrying off with a cellphone to his ear. Something about the way he shuffled off, one leg shorter than the other, his brow beetled with determination and ignorance, reminded me of my distinguished friend. Perhaps it was the pinkie ring and complimentary ballpoint pen from eBay sticking out of his shirt front--I don't know. But heart in mouth, I followed this beast and indeed found myself at the doorway of my friend.

The portal was ajar. A foul odor came from the laboratory. I peered into the darkened enclosure and was somewhat relieved to see my old associate sitting in his Barcalounger, exhausted, trembling.

"Jekyll!" I ejaculated in sheer relief and good humor.

"Come no closer, Bing," he said. As I ignored his request and drew near, I could see his laptop, plugged into his online financial site. "Look," he said in a voice hollowed out by suffering and confusion. "Last Thursday...up 300 points! New housing starts are good. Inflation is not a consideration. Some corporate earnings appear to be swinging back."

Then he picked up a sheaf of newspapers, and something unutterably horrible happened. His voice, always a fine musical instrument, grew guttural, wild and uncivilized. "But look!" he grunted in a mucous-filled baritone, brandishing the papers. "Planned cuts at United Airlines will mean layoffs! Massachusetts is suing First Boston! War with Iraq! Martha Stewart being investigated for fraud! General Electric caught up in accounting issues! Are these opportunities or liabilities? Who can say?!"

He rose to his feet, and the skies above cracked with a gigantic boom and suddenly what stood before me was no longer my old friend but a ravening, irrational beast with hair in its nose and a mind like creamed corn. The creature was laughing. "Ha! Ha! Ha!" it said. "My transformation is complete! I am Mr. Investor! I know nothing but what I heard five minutes ago! One minute I have confidence! The next I have none! I'm an idiot, and I'm going to drive the market to historic growth one day and down to unprecedented destruction of value the next! And I am in control! For the foreseeable future! Hahahahaha!!!!"

I stumbled into the night, completely grossed out. I have not seen him since. But given the way the market has been behaving recently, I have no doubt he is out there. And I have an equally chilling conviction.

He is not alone.

By day, Stanley Bing is a real executive at a real FORTUNE 500 company he'd rather not name. He can be reached at stanleybing@aol.com.