Describe "the game" they play with Robert. How do they suggest they could make the game better?

Caught up in the momentum of their chanting and dancing, they jab at Robert with their spears, at first in jest, and then with more dangerous intent. Frightened and hurt, Robert drags himself away from the crowd, now aware that they are carried away with their game. Roger and Jack talk about the chanting, and Jack says that someone should dress up as a pig and pretend to knock him over. When Robert says that Jack should get a real pig that he can actually kill, Jack replies that they could just use a littlun. There is the uneasy sense that Jack is not joking.