Matthew’s Wallpaper Lion is introduced early in the novel, and functions as an important symbol of social isolation. In Matthew’s bedroom, “high in a corner” above his bed, “there was a piece of wallpaper that, if you considered it from a certain angle, looked like a lion” (18). Feeling ostracized from his family and with virtually no friends to speak to, Wallpaper Lion becomes a winning and faithful companion, fixed to the wall and therefore always available to listen to Matthew’s daily musings.

Things grow complicated when Matthew’s father, without warning, repaints his bedroom walls, essentially robbing Matthew of what he considered to be a true friend. Matthew manages to salvage a small piece of the wallpaper—the part that depicts the Lion’s eye—and resolves to keeping the paper in his pocket for comfort. This compromise proves to be much less effective than when the Lion remained reliably on Matthew’s wall, as is evidenced in Chapter 29, when, following a fight with his parents, Matthew “felt very, very alone” (248) despite having the Lion’s eye in his pocket.

As Matthew continues to make progress toward emotional healing and, specifically, OCD recovery, his reliance on Wallpaper Lion wanes. Toward the end of the novel, when Matthew finally explains his fear of germs to his parents and promises to make good on his decision to get better, he hands the remaining scrap of Wallpaper Lion to his mother and asks that she throw it away.