What threat does the Lord of the Flies make to Simon?
In simplest terms, the Lord of the Flies threatens Simon with the charge that he, Simon, will be seduced by the evil and savagery within himself just like all the other boys on the island. Furthermore, the LotF tells Simon that there is nothing Simon can do stop the snowball effect of savagery.
The Lord of the Flies announces to Simon that he is a part of Simon, a part of all the boys. He foreshadows the end of the story by demonstrating that the boys characters are too flawed to be able to overcome anarchy.