Bonds between these Pokémon are very strong. It protects the safety of its pack by tricking its opponents. Each has the ability to fool a large group of people simultaneously. They protect their lair with illusory scenery. Stories say those who tried to catch Zoroark were trapped in an illusion and punished.
-- Pokémon Black & White/Pokémon Black 2 & White 2 Pokédexes