What's the creepiest passage in literature?

At The Atlantic, Joe Fassler votes for an infamous passage from Cormac McCarthy's The Road:

He started down the rough wooden steps. He ducked his head and then flicked the lighter and swung the flame out over the darkness like an offering. Coldness and damp. An ungodly stench. He could see part of a stone wall. Clay floor. An old mattress darkly stained. He crouched and stepped down again and held out the light. Huddled against the back wall were naked people, male and female, all trying to hide, shielding their faces with their hands. On the mattress lay a man with his legs gone to the hip and the stumps of them blackened and burnt. The smell was hideous.

Jesus, he whispered.

Then one by one they turned and blinked in the pitiful light. Help us, they whispered. Please help us.

The key, he adds: "What is revealed is even more terrifying that what I could have imagined."