What has happened to Jem that makes him say "Its like being a caterpillar in a cocoon, thats what it is like something asleep wrapped up in a warm place. I always thought Maycomb folks were the best folks in the world, at least thats what they seemed like

Jem's has been well protected from the adult world, "wrapped up like a cocoon." All of this changes when he is exposed to the harsh realities of Tom Robinson's trial. Jem is forced to grow up and leave the cocoon that cannot keep him sheltered any longer..... his eyes are open, and he comes to understand that the people around him are not what they always appreared to be.