A/N: To those confused by the more than ambiguous nature of this one, I wanted to play on two primal fears at once- that a loved one being replaced and an unknown predator. I'm not going to exactly say what the creature in this one is, but consider it a human version of the cuckoo- a bird who takes the place of another's offspring.

You’re usually working a late shift, so it’s not uncommon for you to be home past four. You’re a single parent to a teenager. Most would expect you to already have your hands full, but your son is a reliable, dependent boy who has already learned to run home,make dinner for you and himself, do his homework, and even do a few chores before you arrive home.

You trust your child’s responsibility in the regularity of this routine. They would never abscond responsibility to go out drinking, or smoke pot like their friends. You know that you raised them to be better than that. That above all, you trust them.

Which makes today so irregular, when you find the pot on the front porch broken, soil scattered everywhere. This is your first sign of alarm. This is where the only other key to the house is and your son is usually so meticulous…

Fear already bubbles to the surface.

You cautiously enter through the open door and call out his name, only to be greeted with an uncomfortable void of silence. Your steps quick as you search for him throughout the disarrayed house, until a low moan catches your attention.

You look down and see your child dragging their limp body along the floorboards, blood already staining through the wood through an obvious wound in their side.

They've been stabbed. It's as clear as day. Someone has broken into your house and wounded your child.

Someone who still might be here.

As you clasp a hand to your mouth, you watch the very same form you held and fed in your arms raise a shaky, bloodied hand towards you, as helpless and defenseless as they had once been when you held them.

“Mom... help me,” he begs, with eyes glassy and with a slow trickle of blood beginning from the corner of his mouth.

In a blind panic, you rush towards the phone to call for an ambulance, when a hand tears out of the darkness and grabs your wrist. You scream as you’re pulled towards to face the unknown assailant-

It’s your son. Pale and shaking, holding a bloodied kitchen knife.

He looks at you with a terrified desperation you’d never seen before.

“Mom…” he shakily says, “…why did you answer it?”

Behind you, the low pained sobbing cracks into laughter.