Can't sleep?

She opened her eyes. The sound of splashing water in the bathtub woke her, and she lifted her head from the pillow. The splashing sound came again, like someone washing their hands.

She remembered that she hadn't flushed the toilet after her bath that night.

She hadn't read any scary stories about drain monsters. She hadn't read any scary stories at all, so she didn't flinch, her heart didn't skip a beat, or her skin didn't crawl. She got out of bed to go to the bathroom and see who was splashing around at such a late hour. Her mother? She was working the night shift. Her father? On a business trip. Her sister? Sleeping soundly—she always slept like a log. Her younger brother? Quite possibly, since she'd often woken up to his footsteps lately and tried to get him to go back to bed.

 To light her way to the door at the other end of the room, she fumbled with the TV remote on the floor, where it had been after watching yet another ridiculous game show, and clicked the button. The TV itself clicked. The screen lit up, and the host of some late-night program began blaring. Cursing softly, she turned the volume down and crossed her room.

Her sleepy eyes missed the edge of the shadow that slithered under the sofa.

As she stepped out into the hallway, she remembered she was still clutching the remote, and without turning around, she tossed it behind her. For some reason, the remote didn't make a dull thud—it must have landed on the bed. Her mind was so drowsy that she didn't notice the hissing sound cutting through the announcer's voice.

In the hallway, she turned on the bedside lamp and headed for the bathroom.  Again, her eyes didn't register the oddity as she passed the mirror. She didn't notice that someone else had passed by her, slightly behind her, in the reflection.

She reached the slightly open bathroom door, where light was pouring in, and peered inside. Her younger brother stood with his back to the door, bent over and washing his hands.

"Can't sleep?" she asked sleepily, and the boy turned around.

Only when he turned his head so she could see his bluish, eyeless face did she remember that her brother was spending the night at a friend's house that night.

She let out a muffled scream and turned to run.

But before she could take a single step, she heard another splash. The faceless boy returned to washing his hands.

A few hours later, her sister discovered pieces of her body floating in the bathtub.

Are you asking how I know all these details?

 I was the one who followed her in the reflection of the mirror.