She is a minor ally appearing in Part III: Stardust Crusaders.
The unnamed runaway girl first appears disguised as a boy, but later has her real identity revealed. The girl is shown to be a complete liar, telling lies to the Joestar group multiple times, but people barely fall for her stories. She is also a confident swimmer, believing she could reach shore swimming from the middle of the ocean. She eventually develops a crush on Jotaro Kujo, and constantly tags along with the group.
However, she isn't prepared for the group's dangerous trip, becoming heavily dependent on them to survive. As foretold by Jotaro, she only drags them down to the point of risking their own lives. This is especially seen in the battle against ZZ, where she screams for help instead of using the time she had to run.
Initially unnamed, the 2014 Stardust Crusaders anime adaption named her Ann.