Scared Silly (Chapter 1)

Several years ago a writer whose name I don't recall created what was thought to be the shortest possible horror story. It consisted of two sentences:

The last human on Earth sat alone in a room. There was a knock on the door.

The implication is that something inhuman was trying to get into the room, and that was supposed to horrify readers.

That made me wonder about the shortest possible erotic horror story. Maybe it would be something like this:

The last woman on Earth sat alone in a room. There was a cock on the floor.

(Continued next chapter)