Smeargle is an interesting Pokemon from Generation 2. It's unique move Sketch allows it to permanently copy the last move used by an opposing Pokemon, basically meaning it can learn almost every move in the game (there are a few exceptions). Given the simplistic nature of Pokemon GO compared to the main games, how would Niantic go about implementing Smeargle into the game? Believe it or not, by photobombing.
A recent update to Pokemon GO allows players to select any Pokemon in their collection and go into an AR photo shooting mode where you can plop your Pokemon on a flat surface, move around to get a good angle, and snap pictures of them. Starting today though, you might find a little surprise when you snap that picture. As seen in my picture below, Smeargle can randomly photobomb one of your pictures. If this happens, once you get back out to the main map screen Smeargle will appear for you to catch. As for its moves, Smeargle will know the moves of the Pokemon it photobombed, so in my case it knows the two moves my Absol knows. While you can do this multiple times, it's completely random when it does happen and out of dozens of pics I've snapped today, this is the only Smeargle I've seen.