Why does Golding have the boys reenact the pig hunt? What mood does it create? What does it show?

In chapter 7, the boys form a hunting expedition and search for the beast throughout the island. When a boar suddenly appears out of the forest, Ralph throws his spear at the charging boar and successfully hits it in the nose. Jack and the hunters quickly gather around Ralph as he attempts to tell the boys how he successfully struck the boar. Jack then instructs the boys to make a ring and Robert begins acting like a pig. The boys proceed to poke and stab Robert as he starts to scream for them to stop. The frenzy of the group heightens as they strike Robert and chant, "Kill the pig! Cut his throat! Kill the pig! Bash him in!" (Golding, 88). Fortunately, Jack ends the violent game and suggests that they use a littlun to act as the pig next time.
Golding provides a description of the boys reenacting the hunt to illustrate their mindset and bloodthirsty, savage nature. Even as they pretend to hunt Robert, they act like brutal barbarians and demonstrate no sympathy towards him. Golding creates a mood of hysteria, suspense, and aggression throughout the reenactment, which reveals that the boys have completely descended into savagery.