How does the pig tear the boys apart in Lord of the Flies?
The pig, or the beast that the pig embodies, tears Ralph and Jack apart because their approach to fighting it is different, Jack's being direct and violent and Ralph's being logical and reasoned. At the beginning, it appeared that they might find common ground but that quickly vanishes under pressure of the beast, or the fear of the beast.
The fear of the beast also forces boys to choose one or the other side to be on because the thought of facing it alone is too terrifying.
And when Simon figures out what the beast really is and rushes out of the woods to tell the other boys, it is the fear of the beast that causes them to kill him.