What is the name of the Lord of the Flies creature?

The boys call the creature in the jungle "the Beastie."

The "Beastie" is really a dead parachutist, and they kill Simon, mistaking him for the Beastie. It was the evil inside everyone that killed Simon. The imagined creature in Lord of the Flies is variously called... the snake-thing, the beastie and the beast.