The official Pokémon Go social accounts shared a photo of two Trainers who had just traded Pokemon, and it just so happens that the Pokémon pictured are no ordinary, unlucky pocket monsters! Their photo teases the addition of new Lucky Pokémon, which feature a few unique benefits.
Renowned Pokémon Go dataminer Chrales has confirmed that Lucky Pokémon feature decreases Power Up costs, requiring significantly less Stardust. At this time, it appears the Stardust cost receives a 50% reduction. Learn more about farming Stardust and Powering Up Pokémon in our detailed guide.
Lucky Pokémon also feature a unique background animation on the Pokémon’s page, and a new counter has been added to each Pokedex entry displaying how many times you’ve caught a Lucky Pokémon of that type. Presumably, any Pokémon can be Lucky, and it will be entirely random whether you encounter one.
There are no details yet as to whether or not Lucky Pokémon will be a side-effect of trading Pokémon (as in, you trade Pokémon with another Trainer and one or both will become "Lucky") or if you'll be able to encounter them in the wild. If they're encountered in the wild, it's likely they won't be nearly as a rare as Shiny Pokémon.
There also do not appear to be any actual combat advantages, so it is likely that a Pokémon’s “Lucky” status won’t have any effect on its IVs or CP. The discounted Power Up costs are a welcome enough benefit, though, especially if you happen to find a Pokemon that is lucky and has great stats.
No official details about Lucky Pokémon have been shared by Niantic, but we’ll keep an eye out for any official announcement and update with additional details as they're unveiled!