Which is kind of funny, because I've been thinking about the story, too. And so I had to dig out a somewhat different version I recently came across, which I excerpt for you here:
He asked the spirit, What is your name, and the spirit answered, Legion, for we are many. In commanding tones, Jesus said, Leave this man, unclean spirit. And no sooner had he spoken than a chorus of infernal voices went up, some reedy and shrill, others deep and hoarse, some as gentle as a woman's, others as harsh as the sound of a saw cutting through stone, some mocking and taunting, others pleading with the humility of paupers, some arrogant, others whining, some prattling like children learning their first words, others crying out like ghosts in distress, but all begging Jesus to allow them to remain, one word from him could drive them from this man's body, For pity's sake, the evil spirits begged, do not expel us. And Jesus asked them, Tell me, then, where do you want to go. Now as it happened, a large herd of pigs was grazing on the slopes of the mountain nearby, and the spirits implored Jesus, Allow us to enter the pigs. [...] In great excitement the evil spirits made bets, awaiting Jesus' reply, and when he said, Yes, giving them permission to pass into the pigs, they cheered in triumph and inhabited the animals instantly. The pigs, either because of the shock of it or because they hated being possessed by demons, went wild and threw themselves over the cliff, all two thousand of them, and into the lake, where they drowned. The wrath of the swineherds tending these innocent animals was indescribable. [...] They ran down the slope to the water's edge, jumped into their boat, and rowing at top speed, were soon out of danger. [...] Some pigs were lost, a soul was saved, the winner is God said James. Jesus looked at him, his thoughts elsewhere, on something the two brothers watching him wished to hear about and discuss, the strange revelation by the demons that Jesus was the son of God, but Jesus turned to the bank from which they had escaped, gazed at the water, the pigs floating and rolling with the waves, two thousand innocent animals, and he felt an uneasiness rising within him, searching for an outlet, until he could no longer contain himself and exclaimed, The demons, where are the demons, and then he sent up a roar of laughter to heaven, Listen Lord, either You chose poorly this son who must carry out Your plans...or there is something missing in Your powers, for otherwise You would be able to defeat the devil. What are you saying, asked John, appalled by this unthinkable challenge, I'm saying that the demons who possessed the man are now free, for demons as we know don't die, my friends, not even God can kill them, and for all the good I did there I might as well have struck the lake with a sword.
Courtesy of José Saramago, The Gospel According to Jesus Christ, excerpted and italics added by me.
Note: when I mentioned to Mr. Billy how Monkey 0 got me rolling on this particular subject, he said, "If all your writer friends wrote about jumping off a cliff, would you write about jumping off a cliff, too?"
Well, if it was interesting, I would.