What is Simon Strange’s encounter with the beast?

Simon comes face to face with the pig's head on a stick. It is the Lord of the Flies or manifestation of Beelzebub (Devil). The Lord of the Flies speaks to Simon in the voice of a Headmaster. It is an extension of the dark side that Golding thinks exists in all of us. Only Simon has the faculties to find it. In the end, Simon has one of his epileptic fits and passes out.