The first mention of the beast occurs in chapter two during the afternoon meeting. Ralph and Jack both, each in his own way, mention the importance of rules whilst Piggy makes everyone aware that nobody knows where they are. Ralph then comforts them by saying that they are on a good island since there is enough food. It is then that the boy with mulberry-colored birthmark whispers to Piggy about the 'snake-thing' which he later calls a 'beastie.' The boy mentions that it was 'ever so big' and that he had seen in the woods.
Ralph is the first to respond:
“You couldn’t have a beastie, a snake-thing, on an island this size,” Ralph explained kindly. “You only get them in big countries, like Africa, or India.”
When the boy mentions to Piggy that he had seen it in the dark, Ralph suggests that he then could not have seen it. When the boy insists, Ralph mentions that it must have been a dream. He does not, however, find much agreement in the faces of especially the younger boys, although the older ones agree. Ralph also suggests that the boy must have had a nightmare, a statement which drew a similar response.
The boy, though, insists that the beastie will come that night. Ralph's response is to insist that there is no beast. Ralph does not know what more to say and is both amused and exasperated at the same time. It is clear that he wishes to deal with the issue by just denying the boy's fears, which indicates his immaturity and naivety.
At this point, Jack grabbed the conch and declared:
“Ralph’s right of course. There isn’t a snake-thing. But if there was a snake we’d hunt it and kill it. We’re going to hunt pigs to get meat for everybody. And we’ll look for the snake too–”
At this, Ralph shouts that there isn't a snake and Jack asserts that they will make sure when they go hunting. Ralph is annoyed and has no idea of how to respond. The only thing he can do is to, once again, deny its existence. He asserts his conviction a third time, with more emphasis:
“But I tell you there isn’t a beast!”
At this, there is silence. Ralph then changes the subject and speaks about having fun and being rescued. He then focuses the boys attention on the idea of rescue and how they can assist in their discovery. The beast is temporarily forgotten.
Talk about the beast recurs in chapter five when Ralph mentions that things seemed to be breaking up and that there was talk about fear and that 'people were getting frightened.' He mentions:
“But that’s littluns’ talk. We’ll get that straight. So the last part, the bit we can all talk about, is kind of deciding on the fear.”
Ralph wants everyone to be happy and focus on important stuff, not talk about bogies and things which frighten them - they have to decide what it is that makes them so afraid. Jack takes up the conch and says the following:
“So this is a meeting to find out what’s what. I’ll tell you what’s what. You littluns started all this, with the fear talk. Beasts! Where from? Of course we’re frightened sometimes but we put up with being frightened. Only Ralph says you scream in the night. What does that mean but nightmares? Anyway, you don’t hunt or build or help—you’re a lot of cry-babies and sissies. That’s what. And as for the fear—you’ll have to put up with that like the rest of us.”
It is clear that Jack takes an aggressive stance on the issue and feels that the boys who are affected by their fear are a bunch of cry babies. He then mentions an animal and then declares that he is a hunter who has been all around the island and that he had not seen an animal or beast anywhere. He insists that he would have seen it if it were there.
In the end, since the issue could not be entirely resolved and Sam n' Eric had declared that they had seen the beast at the top of the mountain, it is decided to find it. All the older boys then set out to explore the island and suss it out. Piggy is left behind with the littluns.
What the issue about the beast makes clear is the difference in approach by Ralph and Jack. Ralph wishes to rationalise the issue by disclaiming the existence of such a creature - it is only a figment of the boys' imaginations and not real. Jack, conversely, has a much more gung-ho and practical approach. Any threat to their safety must be hunted down and destroyed. His attitude here predicts his actions later, when he turns against Ralph and, with his hunters, seeks him out to be rid of him.