What could the nightmare the little 'un with the birthmark symbolize?

The nightmare experienced by the little 'un with the birthmark in "Lord of the Flies" symbolizes the innate fears and moral dilemmas that arise in the absence of societal structure. The birthmark itself represents the imperfections and vulnerabilities of human nature, highlighting the fragility of innocence. This nightmare foreshadows the boys' descent into savagery and the loss of their civilized identities, reflecting the overarching theme of the darkness within humanity.