This story is crackers.

Unless the passenger you are referring to is a pizza delivery guy in training (and with a long delivery haul), what the hell is he doing appearing out of the blue with three pizzas?

Are you telling me (1) he had them on board during the flight, in which case they would be cold and the plane would be smelly, never mind the story he would have had to come up with at security or alternatively (2) he ran ahead and bought them from some in-airport pizza joint ? In the latter case, I wonder where and how this would be possible.