The second is alteration. This is a detail goes against details already given. This is called a contradiction. For example, in , the villain Revolver Ocelot tells the main character Solid Snake that Big Boss was in his late fifties when he gave his genes to make clones. This was the year 1972. However, in the prequel Metal Gear Solid 3, Big Boss is the main character. The game is set in 1964, but Big Boss is nowhere even close to being in his late forties or early fifties, which is how old he is supposed to be. 