Bogleech.com's 2014 Horror Write-off:
" Better Safe Than Sorry "
Consider this young couple. They are about to leave their flat, and one of them is joking about how paranoid the other is, having several locks on the door and closing every single one of them whenever they go out, no manner how short the excursion. They even make a silly off-hand remark how the other would probably use the little door chain as well if they could do so from the outside.
As they leave the flat, the jokester decides to head down the stairs and wait for the other in the street, knowing that their high-security antics will take a moment.
Now consider that you were inside the flat, and you hear the closing of the locks from the outside, followed by a short moment of hesitant silence.
Then, slowly, several fine, fleshy tendrils would slip through tiny cracks between the door and the wall, as well as through the openings of the locks, and they would rapidly grow in thickness on your side of the door, until they formed a grasping organ of sorts. This improvised hand would then reach for the door chain and hang it in.
“Are you coming?”, you would hear from downstairs, and the one in front of the door would say “I’m there in a second!”, the “second” being the time it took for the tendrils to slip back outside.