This is kinda genius.
An 'inventor' went in front of New York subway users in order to convince them that he was building a time machine, which unsurprisingly didn't convince anyone.
But the occupants of the underground got a bit of a shock when the inventor's future self also made an appearance. And that was just the start of the weirdness....
To see more public pranks of this sort, visit Improv Anywhere here.