Either a moron or a plant.
Not mutually exclusive. Probably both.
Clearly a plant. Otherwise, the media would have identified him by now, and his face would be all over the news and entertainment shows.
My guess is a foreigner, someone who can pull off an American accent. He was on a plane out of the country within hours of his appearance, with his hair dyed and looking (and sounding) much different than he did at the Trump event.
Question is: was he a plant by the Dims, or the GOP-e?