The biggest supertition introduced in the novel is that of Boo Radley. No one really knows what happened in the house to make the boy seclude himself the way he did and continued to do in his adulthood. It is all speculation, and with speculation comes lots of ridiculous superstition. The kids displayed this by daring one another to go into the yard, or run and touch the house and back fearing that just going onto the property would cause some horrible thing to happen. They played "Boo Radley" games where they spoke words as if they were him and acted out events they thought happened. Eventually the superstition wore away as they became older and more mature. The first sign of it was the little trinkets and gum packets he left in the tree for them. It culminated in the night that Bob Ewell attacked the two on the way home from the pageant and Boo killed Bob and carried the very injured Jem home with Scout following in the moonlight. She saw Boo in the room for the first time, and he didn't even have three heads. This was a signal that growing up meant changing--the way they did things and the way they thought about things and people, too.