Sugar Mountain

Sugar Mountain is a girl trapped along with her parents and other people by the tree Stand.

She first encounters Gyro and  Johnny while they're on the way to get the ears and the right arm of the  corpse after stealing  Gyro's Steel Ball.

After a brief introduction, Gyro attempts to search the tree that she lived in for his Steel Ball, however, she uses her stand ability in a series of questions to not only return the ball to  Gyro but also give him money, a gold ore and a few diamonds.

The issue was for Gyro to use it all up before sunset in order to restrict both  Gyro and  Johnny from turning into "fruits" as part of the trees stand ability