Here is a quote about the character Mrs Dubose from the book (from Shmoop) 

"Mrs. Dubose is the dragon. Scout introduces her as "plain hell" (1.14):

Jem and I hated her. If she was on the porch when we passed, we would be raked by her wrathful gaze, subjected to ruthless interrogation regarding our behavior, and given a melancholy prediction on what we would amount to when we grew up, which was always nothing. (11.3)

Despite being confined to a wheelchair most of the time, Mrs. Dubose inspires rage and fear just through the power of her words. Closer up, her appearance alone is enough to gross Scout out:

Cords of saliva would collect on her lips; she would draw them in, then open her mouth again. Her mouth seemed to have a private existence of its own. It worked separate and apart from the rest of her, out and in, like a clam hole at low tide. Occasionally it would say, "Pt," like some viscous substance coming to a boil. 

For Scout, Mrs. Dubose is a distressing, barely human force that takes over their afternoons after Jem goes crazy on her camellias. It's not until after she dies that Scout and Jem get a sense of what's going on behind the drool and venom: Mrs. Dubose is a morphine addict who had vowed to go clean before she died, and enlisted Jem and Scout (without their knowledge) to keep her off the stuff for longer and longer periods of time. Atticus tells the kids the lesson he hopes they've learned from her.

'I wanted you to see what real courage is, instead of getting the idea that courage is a man with a gun in his hand. It's when you know you're licked before you begin but you begin anyway and you see it through no matter what. You rarely win, but sometimes you do. Mrs. Dubose won, all ninety-eight pounds of her. According to her views, she died beholden to nothing and nobody. She was the bravest person I ever knew.' "

As I was going through Karina's papers after her death, I found this writing in the shape of a foot on the back of a more prosaic school assignment

"People always say 'Oh, I'm sorry' or 'Good luck' when I tell them about m y cancer. Little do they know that when they say those things it only makes me feel worse. It is a constant reminder of my cancer and it brings about a melancholy feeling. I much prefer their silent prayers no matter how well meant their feelings are. I also have to wonder about why people try to pretend they know what I am experiencing. They act like cancer and trials can be read just like a book which can be quite irking. When I was in class discussion I felt my blood boil when we were on the topic of Miss Duboce. Their suggestion of her being a shut-in was infuriating. They simply had no clue what it was like to be locked into a bed as I had experienced the helplessness of being bedridden. I stated my view, however, I do not believe many understood. This I found difficult to believe what people were missing. If they walked in me for a day, I am sure their minds would lastingly changed."