"Unique Item (English Edition)", de Milorad Pavic, Dragana Rajkov - Simic .

"How does one make one of those demons and evil spirits enter the room?" said Pushkin in my dream, "how does one recognize it if it does? How does one make it answer one’s questions? What is the Devil in fact? The Devil eats the same as man, but cannot digest a thing. That is because only the Devil does not take part in the global exchange of matter in the Universe. If he has a glass of red ‘Tokay’ wine, instead of urine he will pass red ‘Tokay’ wine once more."