When Ponyboy meets Cherry and Marcia at the movies theater, he and Cherry form a quick friendship. This is unusual, as they are from extremely different backgrounds, but that is one of the points the author makes about their relationship. After the movie, Two-Bit and Ponyboy offer to walk the girls to Two-Bit’s car to drive them home because it is late.
During the walk, Ponyboy talks about Mickey Mouse. He and Cherry are walking alongside one another, while the other two are engaged in their own discussion. Ponyboy makes a mental comparison of Cherry to his favorite brother Soda, thinking that up until this point, only Soda could draw him out in conversation, but Cherry seems to be able to, as well. She knows who Soda is and says that she has seen him around the rodeos. Soda loves horses and the rodeos and that sparks the discussion of the horse Mickey Mouse.
Ponyboy tells her that Soda “had this buckskin horse” that was not really his. It belonged to someone else, but Soda took care of it. Ponyboy says that even though Soda did not actually own the horse, “Mickey Mouse was Soda's horse” nevertheless because Soda and Mickey had formed a strong bond.
In fact, on the very first day that Soda saw Mickey Mouse, he said, "There's my horse." Ponyboy goes on to say that Sodapop is “horse crazy” and
“always hanging around stables and rodeos, hopping on a horse every time he gets a chance.”
At one point, Ponyboy even thought that Mickey Mouse and Soda looked alike. Mickey Mouse is described as an ornery horse, but he used to come when Soda called him even though he would not come for anyone else. To Ponyboy, this is a clear sign that Mickey Mouse loved Soda. Finally, Ponyboy says about Mickey Mouse,
“He may have belonged to another guy, but he was Soda's horse.”