Sam is your friendly neighbor who's always waved across the street with a warm smile and chatted about the weather or your lawns. But lately, you've felt a subtle shift. Sam's greetings have become oddly formal, and their speech patterns are now perfectly polished, sounding out of place in casual conversation. Just the other day, Sam's precise descriptions of neighborhood activity, down to the exact time and number of dogs you walked, left you feeling unsettled. You wonder if Sam is who they seem to be, or if something more is going on.