What do the boys see at the end of Chapter 7 of Lord of the Flies and how do they react?

The boys see the hanging corpse of the dead parachutist. This is significant in that it is (or was) a man who to them represents a beast. They have, particularly in this chapter, become more like beasts themselves in the torture of Robert when they are playing the hunting 'game'. As they see the corpse at night, this adds to its mystery and fuels their belief in The Beast. Ignoring Ralph's suggestion to explore the area in the daytime has drawn them still further into primitive belief which runs alongside their descent into savagery.