His curiosity came in a vague thought bobbing against the surface of his mind, which quickly sharpened and reified. It first verbalised as a question; ‘Why do we talk out loud when we’re alone?’ A conjecture, a guess… it’s because we know we’re not.

There’s perfect offence and there’s perfect defence, to sharpen and develop survival skills. Evolution perfects survival skills, it’s why there are so many different animals with so many various mechanisms. Through the converging visages of his mind, there was another question: ‘Why not perfect hiding? Better question, if there was such a creature, how would we even know it exists?’

He stands before the climax of his analysis, or at least the door to it, the hermetically sealed hatch he used his sonic screwdriver to unlock, and he watches the outer shell of the mechanism turn. Behind this door is quite literally nothing; a barren world of a dead universe, not a single sliver of life. Not a tap, not a click, not a thump, not a thud, not a slither, not a breath. He’s here because if such a creature, whose sole purpose and skill was to hide from view, what would it do when everyone was gone, when there was only one man left in the whole of existence? What would a creature that would only reveal itself to the young, and the old, and the sick and the mad do when it was only him left? He needed to know. The hatch stops rotating in a faint hiss of air as the pressure equalised, and the moment of truth was only seconds away. Was it simply the pressure difference that turned and unbolted the hatch, was it simply the exterior cooling that caused the knocking sound from the other side, or…was there somebody knocking?