All around the game world are acorn trees that drop acorns on the ground, that the pigs can eat and fatten up on. Players can collide with a tree, which may cause acorns to fall, but makes noise and causes the tree to shake. Noises tend to alert the crabs, making them come nearer.
Motion attracts skeletons.
Trees should be evergreen and bear acorns year around. Acorns should appear on the tree and drop at slightly irregular intervals. Collision elements Trees shake when players run into them. If shaken, acorns may drop. A formula will be needed to determine how many acorns drop.