Why is Chapter 8 of Lord of the Flies important to the book as a whole?

As was foreshadowed in the previous chapter, Jack and his hunters continue to devolve into savagery in Chapter Eight. They indulge more and more in stereotypical "native" behavior that emphasizes the use of violence and rituals of song and dance. For these boys the actions are initially little more than a game; when Jack invites the other boys to join his tribe, he explains that the point of this new tribe is solely to have fun. The boys continue to see their behavior as savages as part of an elaborate game, even as the "game" takes on increasingly dangerous and violent undertones. The mounting brutality and impulsiveness of Jack's group in this chapter foreshadows the events of Chapter Nine, in which the boys' behavior moves from mere pretending at violence to actual murder.

There are many allusions and metaphors in this chapter that are directly linked to the major themes in this novel. There is the beast as a metaphor for the darkness in all the boys. Simon is close to completing his role as Christ-figure when he faces the metaphorical beast.