There is a young American man in France. His mother has passed away. He has few friends, and works the thankless job of a bus boy in a prestigious restaurant, but dreams of becoming a chef despite having very little skill.
He returns one night to his humble apartment, which is known to have vermin, and comes across a rat, which he could easily kill or set loose on the street.
But the rat- it is special. It seems to speak to him. Promises him every little thing he desires- talent, fame, and fortune. Recognition and esteem like he has only ever seen from afar; fine company like the wealthy men and women whose scraps he picks at over the sink.
Put me on your head, the rat says. Put me on your head and think of nothing.
It is strange at first, yes. Strange to feel another take control of his life and live it better than he ever could. To see miraculous things created with his own two hands, to feel his feet move in graceful and fantastic ways with a confidence he has never had.
But the rat delivers as he had promised: he receives promotions, notoriety, admiration. He is noticed. Envied. Every day is a waking dream, rubbing elbows with beautiful women and handsome men and influential personalities who lavish him with praise. It is addictive, this lifestyle- never mind that he is only ever truly conscious of it as a passenger of in own brain.
It is when he has reached heights few can ever conceive, with all that the rat had ever promised- a beautiful wife in a beautiful house with all the world in his palm, in possession of all the wealth and success a man could ever want, that the rat says that it is leaving.
Leaving? The rat cannot leave. Everything he is, the rat has provided.
"I have delivered on our bargain", the rat says. "I have brought to you all that you have ever dreamed. What more could you desire? I must live my own life, now."
The man is furious. He is terrified. He destroys the rat, in all of the ways that a rat can be destroyed, until nothing is left of it but a fine smear of marinara sauce.
He returns to the restaurant the next day moving like the shell of something hollowed-out and brittle. He cooks well- his fingers remember the movements, his eyes recognize the patterns, his mouth knows without his asking what orders to speak and what platitudes make patrons smile pleasantly with their straight white teeth.
He retains the talents of the rat. The charm of the rat. All the worldly pleasures the rat had provided him.
Still, it seems, he is little more than a vessel for the talents of the rat.