In chapter eight of Lord of the Flies, by William Golding, Jack and his hunters sharpen a stick at both ends and place the dismembered head of a pig on it as a kind of offering. Jack says, “This head is for the beast. It’s a gift.” Jack knows that he is helping his hunters to be less afraid by suggesting this token as some kind of appeasement for the imaginary beast they are all at least somewhat afraid of; however, it is literally just a rather gory pig's head on a stick.
Simon has seen the entire incident from his place of solitude, the place he goes when he needs to be alone. The first thing we learned about Simon is that he is prone to fainting, and the description of this conversation with what is called the Lord of the Flies suggests that it is all some kind of a waking dream.
There were no shadows under the trees but everywhere a pearly stillness, so that what was real seemed illusive and without deﬁnition.... In Simon’s right temple, a pulse began to beat on the brain.
Th Lord of the Flies mocks Simon as a "silly little boy" for thinking that the beast on the island is "something you could hunt and kill." The final words the Lord of the Flies speaks to Simon are a threat, After mocking him and taunting him, the Lord of the Flies says:
“I’m warning you. I’m going to get angry. D’you see? You’re not wanted. Understand? We are going to have fun on this island. Understand? We are going to have fun on this island! So don’t try it on, my poor misguided boy, or else—”
What he is telling Simon is that anyone who tries to interfere with the unrestrained savagery which has been released on the island (the boys' own natural desires and inclinations) will not be tolerated. In fact, he says that if Simon tries to do anything to stop the savagery, Simon will be killed by "Jack and Roger and Maurice and Robert and Bill and Piggy and Ralph." It is a surprising list because Piggy and Ralph are Simon's friends, but it is a prophetic statement. Somehow Simon knows what is going to happen to him, and yet in the next chapter he still tries to warn them.
The final act in this scene is Simon's fainting, a reminder that this was not an actual conversation but more of a realization that the sensitive Simon is having with himself; he realizes that it is they who are the beast and it is their unrestrained human nature that has caused the evil on this island.