I used to play that game! Simpler times! I called it doppelganger, and I would just shout random celebrities names, as if I was seeing the real celebrity, but it was just someone who looks slightly like them. I would have loved to get selfies with these dopples and just pretend I thought they were the real thing to other people, even when they looked almost nothing like them. Until it was so obvious I was taking the piss, there was no fooling anyone any more. Then I would keep doing it just to be annoying! It would never lose flavour.