"His ordinary voice sounded like a wispier after the harsh note of the conch" The conch is a symbol for the power of command. The conch brought the kids to the point of origin and straightened them out. The kids cling to the conch because they crave rules, power and rigidity. As soon as the conch lost its power, the kids converted to savagery.
At once the crowd surged after it, poured down the rock, leapt on to the beast, screamed, struck, bit, tore." The kids did not even think during the feast, their brains were disengaged and only their savage instincts were present. This a symbol for letting group dynamic/hysteria get the better of you. This is very common during concerts and riots.
Preposterous Poached Pig
"Piggy and Ralph, under the threat of the sky, found themselves eager to take a place in the demented but partly secure society" This is a symbol for the security in society and its numbers. People conform to the norms because that gives them something to cling unto, it gives them security. Your society may be targeting one anothers but you have security because the're not targeting you.
The Big Boy Beast
"Jack pointed suddenly.'His specs – use them as burning glasses!' Piggy was surrounded before he could back away." (160) Piggy's glasses become a technological advancement for the boys. The boys use their knowledge to infer that the glasses can be used to make a fire
"Ignoring the flies, the spilled guts, even ignoring and indignity of being spilled on a stick." This is a symbol for the protective ignorance. The character bond himself to the brutal and ugly truth of death. He did not want to accept mortality and its innocent end. The character Simon that death didn't care who you where and that everyone looked the same dead.
"Maybe there is a beast… maybe it's only us." Simon comes to the realization that the beast is most likely a figment of their imaginations. The beast symbolizes the boys fears and the boys cope with these fears by embodying them into this beast.