1000 Pokémon and the Thieves (とうぞくと1000びきのポケモン) has been shown in CoroCoro. It will be a free download for Nintendo 3DS owners and is a tie-in to the upcoming Diancie and the Cocoon of Destruction movie. It will be released on June 5 in Japan. The StreetPass feature will allow you to gather more Pokémon which you can use to battle the thieves. The download will be available for only a limited time.
The game’s art style seems to feature Pokémon sprites which look like paper cut-outs. We’ll get clearer shots when it is officially revealed on May 15th.