In Chapter 7 of William Golding's novel Lord of the Flies, the boys are tracking a wild boar through the woods. Ralph, newly taken with the intensity and adrenaline rush of hunting wild game, excitedly boasts of having struck the boar's snout with a spear, although the possibly wounded animal did escape. The boys reflect on their adventure and talk among themselves of the hunt. While Ralph continues to try to capture the attention of the other boys, and while Jack points out his wounded arm, allegedly the result of a too-close encounter with the boar's tusks, Robert, one of the bigger of the children, begins to simulate the sounds and actions of the boar, prompting some of the other boys to similarly pretend to be attacking the animal. Very quickly, however, the boys get carried away with their game and begin to actually physically assault Robert, treating the hapless boy like the wild game they hope to kill:
They got his arms and legs. Ralph, carried away by a sudden thick excitement, grabbed Eric's spear and jabbed at Robert with it. "Kill him! Kill him!"
All at once, Robert was screaming and struggling with the strength of frenzy. Jack had him by the hair and was brandishing his knife. Behind him was Roger, fighting to get close. The chant rose ritually, as at the last moment of a dance or a hunt.
"Kill the pig! Cut his throat! Kill the pig! Bash him in!"
Robert is not amused by this frenzy of activity directed at him. He is terrified by the attacks and taunts of the other boys. Even Ralph, presumably the personification of civilized order and decency, gets carried away, grabbing at the flailing Robert. When, finally, the boys calm down and Robert is released from their grasps, the terrified boy suggests that, in the future, the gang focus its attention on a real pig, noting that "you've got to kill him." This observation provokes a chilling response from Jack, the sadistic leader of "the hunters," who suggests using "a littlun." "Littluns," of course, are the smaller, weaker, more defenseless children who are easy prey to the larger boys.
This scene in Lord of the Flies is more than a little symbolic. Golding has divided the boys into two main groups: those who follow Jack and those who follow the more peaceable Ralph. When the assembled boys begin to play their impromptu game, it becomes very apparent that even the more civilized of the group, represented by Ralph, are prone to the hysteria associated with the breakdown in social order and the propensity for mob rule to dominate the surroundings. Ralph's participation in the hunt for the boar and in the sadistic attacks on Robert illuminate for all of the boys the dominance of the culture represented by Jack.
He says they need a real pig rather than a pretend one because he just about got killed when he was pretending to be the pig.
This episode happened in Chapter 7. The hunters had been out hunting a pig and they almost got one. Unfortunately, they let it get away. So when they came back, they were still pretty pumped up and were also pretty frustrated. They started dancing, showing what had happened. Robert got in the middle and pretended to be the pig. They started jabbing him with a spear and actually hurt him.
So he says they need a real pig so they can actually kill it.