Jack must destroy Ralph for savagery to prevail over civilization. In the jungle, Ralph comes upon the skull of a pig hung on a spear staked into the ground. He punches it and the skull splits.

Why does Jack want Ralph dead?

In the novel Lord of the Flies, Jack Merridew wants to kill Ralph in chapter 12 because he has undergone the same slow and gradual breakdown of civilization that has affected all of the boys.

Why did Jack become evil in Lord of the Flies?

In Lord of the Flies, Jack represents the savagery or evil in man. He loses his ability to remain civilized while he is stranded on the island. He gives in to his innate savagery and becomes dehumanized. He becomes a wretched evil person.

Jack then has his hunters roll massive boulders from the top of Castle Rock into the thicket in hopes crushing Ralph or flooding him out of his hiding spot. Ralph realizes that he cannot remain inside the smoke-filled thicket and Jack successfully drives Ralph out into the open.