I - do have a stupid idealistic teenager who might for real try to befriend someone in a wacked-out costume like that, if you think that could go somewhere OTL Though not if he catches them committing an obvious crime, so.

Alternatively, Yosuke could catch him in the act and maybe inadvisedly sic a ninja demon on him without managing to catch catch him, or he could get victimised somewhere along the line because he's a newbie in town and just that chronically unlucky, or... basically whatever (if anything) sounds good, tbh :')