The blue Mustang represents the Socs wealth as well as the danger they pose to greasers. When Ponyboy or another greaser spots the Mustang, he knows trouble is coming. As the novel progresses, however, and Ponyboy comes to understand and feel compassion for the Socs, the Mustang loses some of its power to intimidate. Ponyboy actually sits inside of it when Randy and he talk about the church fire and the rumble.