In chapter 5, as the boys discuss what the beast is, what do they decide that the beast can eat?"The Lord of the Flies" by William Golding

....Then Piggy held out his hand. 'I don't agree with all Jack said, but with some. 'Course there isn't a beast in the forest.  How could there be?  What would a beast eat?'

'Pig.'

'We eat pig.'

'Piggy!'

In Chapter 5 of "Lord of the Flies" as the boys discuss their fear of the beast, the logical Piggy tries to convince that a beast cannot exist since it has nothing to eat, but the boys reply that it, like them, can eat the feral pigs on the island.  That they call out Piggy's name after saying the common noun pig is significant.  For, this heckling of Piggy foreshadows the cruel death of the Piggy and the death of the rational element as the predatory,  evil nature of the boys surfaces later in the novel.  The beast, which is the inherent evil in the boys, can eat what they eat since it is, indeed, they.