Jack actually makes several revelations to Ralph and Simon during Chapter 3 of Lord of the Flies. The three boys were in the forest, discussing the destruction of the fire; meanwhile, Jack was busy with his head to the ground, looking at the flattened tendrils over which pigs had trodden. Jack tells the other boys that he had let his hunters go swimming, but he had to go on.
The madness came into his eyes again.
"I thought I might kill."
Jack had not yet killed a pig, but his bloodlust was overwhelming, and he promised he would kill--"Next time!" Later, Jack admitted that when he was hunting alone, deep in the woods, he felt as if it were not he that was the hunted--
He flushed suddenly. "There's nothing to it of course. Just a feeling. But you can feel as if you're not hunting, but--being hunted, as if someone's behind you all the time in the jungle."