Anyway, below is a passage from Jeff VanderMeer's "The Strange Case of X," one of the short stories City of Saints and Madmen. This part is a story within the story, a fable that X has written to explain what it's like for him, being a writer.
By this time it was dusk. He knew it was dusk because he could feel the dusk inside of him, choking his lungs, moving across that part of him which housed his imagination. He coughed up a little darkness, but thought nothing of it. There is a little darkness in every writer. And so he sat down to dinner with his wife and her daughter and they asked him how the writing had gone and he said, "Rotten! Horrible! I am not a writer. I am a baker. A carpenter. A truck driver. I am not a writer." And they laughed because they knew he was a writer, and writers lie. And when he coughed up a little more darkness, they ignored it because they knew that there is a little more darkness in a writer than in other souls.
All night the writer coughed up bits of darkness - shiny darkness, rough darkness, slick darkness, dull darkness - so that by dawn all of the darkness had left him. He awoke refreshed. He smiled. He yawned. He ate breakfast and brushed his teeth. He kissed his wife and his wife's daughter as they left for work and for school. He had forgotten the darkness. Only when he entered his work room did he remember the darkness, and how much of it had left him. For his darkness had taken shape and taken wing, and had flown up to a corner of the wall where it met the ceiling and flattened itself against the stone, the tips of its wings fluttering slightly. The writer considered the creature for a moment before he sat down to write. It was dark. It was beautiful. It looked like a sleek, black manta ray with cat-like amber-red eyes. It looked like a stealth bomber given flesh. It looked like the most elegant, the wisest creature in the world. And it had come out of him, out of his darkness. The writer had been fearful, but now he decided to be flattered, to be glad, for he had helped to create a gorgeous apparition. Besides, he no longer coughed. His lungs were free of darkness. He was a writer. He would write. And so he did - all day.
I found these pictures - and several more - here.