Datamined last month, Team Rocket and Shadow Pokémon have started appearing in Pokémon GO. At the time of writing, it appears they only appear at some Poké Stops – much like previous features such as Raids. While the level cap appeared to be level 40, this may no longer be the case.

Thus far, we know the following:

• Team Rocket will appear at Poké Stops at random, and disappear after 30 minutes. Their appearence rate is quite low for now. The Poké Stop will turn dark blue and then black when you are near it, and the cube above it from a distance will spin oddly.
• You must battle a Team Rocket grunt to have a chance at catching their Shadow Pokémon. This is done with Premier Balls, akin to how you catch Raid Boss Pokémon. Shadow Pokémon all have a purple aura and red eyes.
• Upon being captured, the Shadow Pokémon will know the move Frustration and be set to a lower level.
• It costs Stardust and Candy to purify a Shadow Pokémon. This cost varies on the species.
• Upon purifying the Pokémon, Frustration will change to Return, and it becomes a level 25 Pokémon (and hence has an increased Combat Power – CP). Powering up and evolution costs from then on are decreased by 10%, as a reward for purifying. Each stat’s IV (Individual Value) will go up by 2 points. (The red eyes and aura will disappear though.)

Currently Shadow Pokémon available include Bulbasaur, Charmander, Squirtle, Rattata, Zubat, and Snorlax.

We’ll update with more information as it filters through.

Thanks to Pichu for the heads up.