The Rats in the Walls puts players in the same position as the narrator of the H.P. Lovecraft story of the same name – that is, they don't know whether or not rats truly scamper behind the walls of their residence. In the game, one player is the Giver and starts the round with the dice cup and a single die, which shows one rat on one face, two rats on another face, and no rats on the remaining four faces. The Giver places the die in the cup, shakes the cup, places it face down, then peeks inside. He then claims to hear no rats behind the walls or some number of rats. If he says no rats and the next player – the Receiver – believes him, the Receiver becomes the new Giver, adds a die to the cup, and the game continues; if the Receiver doesn't believe him, then he lifts the cup. If no rats are present, the Receiver loses one "brain" scoring token to the Giver; clearly he's touched in the head if he's hearing rats where none exist. If rats are present, however, then the Giver loses two brains, giving one of them to the Receiver. The Caller's an even worse case! If the Giver claims that rats are present, he must pay one brain, then the Receiver taking the cup can call him (with penalties going one way or the other) or he can believe the Giver, handing over one brain to the Giver as the sanity cost of accepting such nonsense. The Receiver can then either pass the cup along to the next person or he can add a die to the cup, shake all the dice, and make another claim about the number of mice in the walls, with this number being at least one larger than the previous number. In this case, the Receiver becomes the Giver, and the round continues as before. Once one player has lost all of his brains, the game ends, and the player with the most brains wins.