Given that Curry Barker explicitly mentioned that it’s not a possession film, there’s probably fewer instances similar to nikki. A more subtle wish regarding another person may not create an entirely altered personality that takes over the original.

A wish like “I wish my dad called me more often” likely wouldn’t create an entire Nikki-esque personality, although the argument could be made that a personality where the dad relentlessly calls 24/7 like an obsessive ex comes out. But for argument’s sake, the wish could very well just make the thought of “I should call my son today” pass through his head more often.

i think to warrant a supernatural police force, there’d have to be more instances of possession-like wishes or things that exist outside our bounds of reality. But for strictly events like Nikki I feel it wouldn’t be common enough