Coraline

The old black key felt colder than any of the others. She pushed it into the keyhole. It turned smoothly, with a satisfying clunk.
Coraline stopped and listened. She knew she was doing something wrong, and she was trying to listen for her mother coming back, but she heard nothing. Then Coraline put her hand on the doorknob and turned it; and, finally, she opened the door.
It opened on to a dark hallway. The bricks had gone as if they'd never been there. There was a cold, musty smell coming through the open doorway: it smelled like something very old and very slow.
Coraline went through the door.
She wondered what the empty flat would be like--if that was where the corridor led. Coraline walked down the corridor uneasily. There was something very familiar about it.
The carpet beneath her feet was the same carpet they had in her flat. The wallpaper was the same wallpaper they had. The picture hanging in the hall was the same that they had hanging in their hallway at home.
She knew where she was: she was in her own home. She hadn't left.
She shook her head, confused.
She stared at the picture hanging on the wall: no, it wasn't exactly the same. The picture they had in their own hallway showed a boy in old-fashioned clothes staring at some bubbles. But now the expression on his face was different--he was looking at the bubbles as if he was planning to do something very nasty indeed to them. And there was something peculiar about his eyes.
Coraline stared at his eyes, trying to figure out what exactly was different.
She almost had it when somebody said, "Coraline?"
It sounded like her mother. Coraline went into the kitchen, where the voice had come from. A woman stood in the kitchen with her back to Coraline. She looked a little like Coraline's mother. Only...
Only her skin was white as paper.
Only she was taller and thinner.
Only her fingers were too long, and they never stopped moving, and her dark red fingernails were curved and sharp.
"Coraline?" the woman said. "Is that you?"
And then she turned around. Her eyes were big black buttons.
"Lunchtime, Coraline," said the woman.
"Who are you?" asked Coraline.
"I'm your other mother," said the woman. "Go and tell your other father that lunch is ready."

The moral of the story: unlocking doors that usually open onto brick walls is always a bad idea. Don't miss this MPR interview with Gaiman where he reads this excerpt and others. I mean, if you like getting the heebie-jeebies, that is.