Smeargle Pokemon GO is a community urban legend. It can't be encountered by itself on the map. Certain specific measures must be taken if trainers would like to add Smeargle to their PokeDex or party.
Smeargle is a normal-type Pokemon introduced to the games in Generation III. It is known as the "Painter" Pokemon and has the unique move "Sketch" which lets it copy its opponents' moves in battle. To this end, it has a similar feature concerning its moveset in Pokemon GO. Its PokeDex number is 235.
Smeargle Pokemon GO: How to Catch
Catching Smeargle is much simpler than it sounds. All you need is your phone, an open flat area, and a few of your favorite Pokemon in your inventory.
To start, open your snapshot feature and select any Pokemon you'd like. You'll be snapping pictures for a little bit so make sure it's a creature you'd actually like to see. Take photos liberally as you want to give Smeargle as many chances to appear as possible. Once you think you've had enough, exit the camera mode.
Now, scroll through your photos. You're looking to see if Smeargle may have photo-bomed them, which is hard to miss. Its face will be staring directly into your lens in one of your photos. If none of your photos have it then you'll need to go back and take more.
Exiting the photo selection will bring you back to "the wild" where you will find a wild Smeargle wandering the map around you. Now's your chance to catch it as you would any other Pokemon.
Be aware that, despite its extraordinary means of summoning, Smeargle will behave like any other Pokemon during an encounter. It can run away from you in a moment's notice and may be difficult to catch. You can only encounter one Smeargle per day, so be careful.
Smeargle Pokemon GO Best Moveset
Remember when we mentioned Sketch for Smeargle? Well, that comes in handy here. Smeargle will copy the moves of the Pokemon it appears in a picture with. Because of this, there is no real "best moveset" for Smeargle. That's up to the player's discretion of which moveset they would like a duplicate of.
Smeargle cannot learn Transform and its moveset will consist of a charged and a quick attack.
Regardless of moveset, however, Smeargle is useless in battle. It has a maximum CP of 431, which means it essentially exists as a vanity catch and nothing more.