There are two types of fear, the fear that bites and the fear that creeps. Nathan Bland, the teenage protagonist of the horror story that David Mitchell recently published on Twitter, has had a strong dose of the first. He’s been mauled by a bull mastiff, which ‘pulled skin off my cheek like skin off roast chicken' and 'shook me like a doll, my own blood blinding me'. The dog still stalks his dreams. When Nathan and his mother arrive at the house of Lady Briggs, an aristo his mother is keen to impress, a dog barks and he feels a pang of terror - ‘my lungs fill with dark’ – before he realises that it’s ‘only a little yappy thing’. Later, Nathan plays a game of ‘Fox and Hounds’ with Lady Briggs’s creepy son Jonah. He’s running, trying to catch Jonah up, when he hears the mastiff behind him. Suddenly it appears with Jonah’s bloody head dangling from its jaws. Nathan runs into Lady Briggs’s house, slams the door and blames the apparition on the Valium he took earlier.