Your doctor had an unusual way of grinning.
You think about it as you lie in one of his examination rooms, biting absent-mindedly at your nail, a dark IV dripping into your arm. When it slurps away to nothing, the nurse replaces it.
The doctor said to wait and relax. The IV would kick in about an hour, and he'd be back then.
You nibble away at a little corner of your index finger and try to count ceiling tiles.
You think about the doctor's smile again. Something about it was vaguely sinister. He showed a lot of teeth.
You keep biting.
How many times has the nurse changed the bag now? Four? Five?
How long has it been?
A sharp snap wakes you up - you chewed off your entire nail. Your finger is killing you. Now that you think about it, though, everything hurts. Your heart is pounding. Your head feels like it's in a vice.
And then the blood comes.
It leaks out of your fingertip, slowly, thickly, like molasses, and, unbelievably, it's as black as night. Clots exposed, it stretches like gum before it breaks, splashing to the ground leisurely.
As you collapse to the floor, surrounded by mountains of empty IV bags, gasping for breath, you watch the the doctor stroll in, grinning.