What does Ralph do to the pig's head at the end of the novel Lord of the Flies?
At the beginning of Lord of the Flies there is a definite attempt by the boys to create their own community which will function in a way that "grown ups" would expect. Even Jack acknowledges the need in chapter 2 for "rules" reminding the boys that they are "not savages. We're English..." Although reluctant at first, Jack has accepted Ralph's position as chief and discusses how he will ensure that the choir boys who are now his "hunters" will take care of the signal fire.
By the end of the novel, the order and good organization of the boys no longer exists. The conch which represented the closest thing to democracy for the boys and which had been so significant when Ralph was voted as chief is no more than "a thousand white fragments" (ch 11). Simon and Piggy are dead and Ralph is alone.
When he comes across the pig's head there is little hope for rescue or even for Ralph's survival as Jack hunts him like he would a pig. It is ironic that as Ralph considers the possibility that Jack's hunters might leave him alone, he compares the "lifeless" skull which is all that is left of the pig's head, to the conch as it "gleamed as white as ever the conch had done" (ch 12). The power has shifted and now lies with Jack.
Ralph wonders about the skull and is filled with "a sick fear and rage" upon which he punches the skull but to no real purpose except that now that it has broken into two pieces its grin is "six feet across." Ralph takes the stick which Jack had so proudly instructed Roger to "sharpen... at both ends" (ch 8) and now it is Ralph who holds it as he would a spear. Ralph does not turn his back on the skull as he backs away from it and continues in his quest to protect himself.
Ralph's reaction to the pig's head on a stick serves as a counterpoint to Simon's vision of the Lord of the Flies. Just as the sow's head had come alive to Simon to reveal that it was the Beast within the boys, the reason why things are the way they are, so the now picked-clean skull seems almost sentient to Ralph, "like one who knows all the answers and won't tell." It fills Ralph with "a sick fear and rage," causing him to strike out at it. The first time he hits it, it bobs back at him, so he punches it with his fist, causing his knuckles to bruise. He successfully breaks it into two pieces, which fall to the ground about six feet apart from each other. This results in its grin being "six feet across." Thus Ralph has has fought against the Beast but not exactly prevailed. It remains "grinning against the sky" as he backs away from it, holding the stick it had been on as a spear.
This scene symbolically represents Ralph's battle against "mankind's essential illness." Ralph has been sickened by the descent of the boys into depravity, especially by their murder of Simon, for which he knows he shares the guilt. He has done what he can to fight the darkness, taking Piggy to Castle Rock to try to regain his glasses. The result of that effort was not to stifle the Beast within the boys, but only to increase its mockery, for in the end the boys murder Piggy with the boulder and become emboldened to hunt and kill Ralph—just as Ralph's attempted destruction of the head served to exponentially magnify its wicked grin. Jack's backing away from the head, spear in hand, represents his final effort to avoid being killed by Jack and his tribe.
As the other boys are enjoying the meat at the feast, Ralph hides close by, eating some fruit. Trying to decide whether to meet with Jack for a last chance at reconciliation, Ralph comes upon Simon's old hiding spot. The pig's head is there, mounted on a stick; it is now nothing but bone, its flesh eaten by the flies. Ralph thinks the skull is smiling at him, knowing his own thoughts, so he strikes out at the head. The first blow does the head no harm, and it still smiles at Ralph, so he hits it again and again. Ralph leaves the skull broken on the ground; with aching knuckles, he takes the stick to use as a spear.