The pigs head
Jack's group sacrifices the head of a pig to the beast, placing it on a stick as an offering. This gruesome gesture symbolizes their descent into savagery and their willingness to appease the imagined beast.
The head of a sow on a stick
By their adoption of superstitious beliefs and practises such as leaving an offering for the "beast."
THE GRAINS GROUP, SILLY!
Samneric
Jack and his savages planned to stay on the beast's good side by offering it sacrifices in the form of animal carcasses. They believed that by making these offerings, the beast would be appeased and not harm them. This was a way for them to maintain control and power within their group.
Ralph
one of jacks group throws a big rock off the mountain and lands on Piggy's head and dies.
Sam'n'eric
Jack warned his tribe about a number of things. Firstly that if they went hunting they should avoid the mountain and leave the heads of their kills as an offering to the beast. He also warned them to be on their guard as 'the others' (Ralph's group) might try to sneak in, to 'spoil things.' After consideration Jack added that the beast might also try to come in.
The two reasons of why jacks group is more exciting than Ralph is because jacks tribe hunt and have a feast and have fun.
Simon