Commonly used to refer to a girl with whom you are considering courtship/elopement/copulation/mating/etc. Typically used by people who are less than attractive to begin with; therefore their person-of-desire is considered "prey".
"Spot any PV's (potential victims) tonight at that house party?"
"I'm going to walk around the club and look for some PV's. I'll report back to you with the results."