What did the boys of Lord of the Flies think the beast was?

When it was initially mentioned by the littlun with the mulberry coloured birthmark on his face the beast was described as being a snake-thing that turned into creeper things. Jack later describes an unseen presence which he sometimes feels is hunting him when he is alone in the jungle. During a meeting many wild possibilities are raised, such as suggesting that the beast might be a giant squid or even a ghost. Simon is of the opinion that the beast is simply themselves while Ralph has always insisted that there is no beast at all. When Samneric claim to have been chased by the beast their description includes wings and sharp claws. Towards the end of the book, after Jack and his tribe have left offerings for the beast, Jack raises the possibility that the beast might be able to disguise itself and also offers the opinion that they couldn't kill it. So in short the boys variously thought that the beast was; a snake, a giant squid, a ghost, some sort of flying creature and later a god like thing that could alter its appearance Alternatively the possibilities were also raised that it might simply be a product of either nightmares or an over active imagination, it might also be a projection of the evil within themselves or simply nothing at all because there was no such thing as a beast.

The littlun with the birthmark disappeared after the fire.