Why do you think Simon is acting different? What do you think has happened to him?

Simon is Golding's Christ-figure meaning that he embodies the traits Christ was said to have. Simon likes all the boys including Jack. There is however always negative energy and the threat of violence. Simon can't bear this. That is why he prefers to be alone. Explaining an idea so evolved and metaphorical as mans' inherent evil is way beyond the others' comprehension. Most of them mock and jeer at what they do not understand. Simon hates this bad energy. Simon dies in the end just at Christ had to.