If you have either Raikou, Entei or Suicune in your Pokemon Heart Gold/Soul Silver games and you transfer it to your Pokemon Black/White, you will be able to gain access to the Lostlorn Forest area. In this place, you will find someone who mentions a Pokemon that has been known to create illusions. You will find a Pokemon matching one of the beasts that you didn't transfer over. If you send over Raikou, you'll see Entei in Black/White. If you send over Entei and you'll see Suicune in Black/White. If you send over Suicune, you'll see Raikou in Black/White. When you attack, you'll see that it is in fact a Zoroark. This is the only way you can capture Zoroark. If you capture Zoroark, it's attacks will be Fury Swipes, Faint Attack, Scary Face, and Taunt.
Added by: Forgoten_Scars Mar 7th 2011, ID#15349