Oh, it gets even more disturbing. The killing of the pig gets so intense, that the boys aren't thinking about food any more: they're just ecstatic about holding so much power over a helpless creature, that they can do whatever they want to it with no repercussions. The whole thing reads like a gang-rape scene. You could replace the word "spear" with "penis" and the effect would be pretty much the same.
They surrounded the covert but the sow got away with the sting of another spear in her flank. The trailing butts hindered her and the sharp, cross-cut points were a torment. She blundered into a tree, forcing a spear still deeper; and after that any of the hunters could follow her easily by the drops of vivid blood […].Here, struck down by the heat, the sow fell and the hunters hurled themselves at her. This dreadful eruption from an unknown world made her frantic; she squealed and bucked and the air was full of sweat and noise and blood and terror […]. The spear moved forward inch by inch and the terrified squealing became a high-pitched scream. Then Jack found the throat and the hot blood spouted over his hands. The sow collapsed under them […].At last the immediacy of the kill subsided. The boys drew back, and Jack stood up, holding out his hands. "Look." He giggled and flecked them while the boys laughed at his reeking palms. Then Jack grabbed Maurice and rubbed the stuff over his cheeks . . . "Right up her ass!"
And also note, as stated before, these are twelve-year-old boys.
The hazy descriptions of the physical Beast, in truth the dead pilot of a fighter that was shot down and killed while ejecting, his parachute dragging his body eerily about in the wind, in the dark.
The titular pig's head, eaten clean by flies and described to have the voice of them in the psyche-shriveling sequence when he speaks to Simon.
Near the end of the book, when Ralph is in his hiding place and hears a savage coming. He first hopes that it might be Sam & Eric, who'll just pretend that they didn't see him, but as the figure emerges he comes face to face with Roger. Cue Ralph screaming and running for his life.