In piggys asswhole
Initially, Jack and his group viewed the beast as a physical creature to be feared and hunted. However, as the story progresses, their perception of the beast evolves into a symbol of their own inner savagery and fear. They come to see the beast as a means to justify their increasingly violent and chaotic behavior on the island.
Jack's answer to questions about the beast is to say that, "if there is a beast we will hunt it and kill it." Ralph keeps insisting, "but there is no beast!"
they went after the beast but jack decide to forget the beast and play rolling rock
First Jack drops them and ends up breaking a lens, then toward the end of the book Jack's group comes and takes them.
jack has taken everything from everyone already so why would he have to take glasses that wont help him in anyway.
Simon
he is very sad and cries at the end of the book because of piggys death
Kill it.
by killing people and giving them to the beast "sacrafice"
Jack says they will leave the head of a sow for the beast as an offering in Chapter 8. He believes it will appease the beast and prevent it from attacking the boys.
Jack's denial that they killed the beast reveal about him that beast still exists. His plan that they keep on the "right side of the beast" suggest that people frequent make offerings to satisfy the beast. I think Jack truly believe there's a beast because he had seen it on the mountain top. His continuing to promote the existence of the beast to the others give him advantage over them by making obey him if they want to be safe!