Why is percival's revelation that the beast comes from the sea frightening?

Percival tells the boys that the monster comes out of the sea in squid shape and afterward is a phantom ashore, so nobody can see it, however despite everything it assaults its prey.

Being trapped on an island without any grown-ups for solace could be exceptionally terrifying to a little kid! Such is the situation with Percival in William Golding's celebrated novel Lord of the Flies. Percival first winds up known as the 'littlun' who cries constantly.