[@ERode]

Okay, an idea's forming

My girl was a track-and-field athlete. Not world-class, but good enough to catch the attention of some suits who wanted a physical street-level Hero. They didn't give her a gimmick but her particular style of parkour (which she had no prior background in) was likened to a scurrying rat by some tabloid and that stuck. She's Ratgirl now and gets Rat powers.