Like Platinum, HeartGold & SoulSilver, Black & White features an event that unlocks when you send over certain Pokémon from real-life events. One of these features Zoroark.
When you send the alternate coloured Raikou, Entei or Suicune that you obtain for pre-booking tickets for the movie Phantom Champion Zoroark in Japan, and at some to be confirmed events outside of Japan over to Black & White, you will get access to a special Zoroark battle. This battle takes place
The Zoroark you face is at Level 25 so it'll probably be best to use a low levelled Pokémon, such as the Legendary Beast you sent over if you haven't trained it. However, this battle is not all that it seems
Since Zoroark has the new ability, Illusion, it will frequently change its appearance into another Pokémon. It would seem that it changes its appearance to the appearance of the other legendary beasts, similar to the movie. However, from what we can tell, its type doesn't change so you'll need to remember that you're battling a Dark-type Pokémon.
During the battle, Zoroark will revert back to its standard appearance when you have dealt enough damage. This will be your chance to capture it.
This event can only be accessed once