Illusion is an Ability unique to only Zorua and its evolution, Zoroark. Illusion changes the appearance of a Pokemon or Pokemorph to anyone whom views it; though the effect is only aesthetic.
Illusion users can create a generic copy of any human or Pokemon/morph species, and randomize unique features to create someone who does not actually exist. The Illusion is nearly complete - altering a viewer's sense of smell, touch and sound (except voice). A Zoroark-morph impersonating a Snorlax-morph would smell like a Snorlax, feel like a large body if hugged (though one would still actually be hugging the fox inside), and have the appropriate noises of heavy footsteps when they walk - except the Zoroark would still speak with their natural voice. It is possible for an Illusion user to perform a perfect copy of an individual, but it requires great skill and training. Young and inexperienced users may create imperfect Illusions, such as a child Zorua-morphs' black tail showing on his copy of a human.
Illusion users may also copy or generate worn accessories and clothing, including masking their own clothing as a Zorua or Zoroark-morph.
There is no limiting distance on the ability - a viewer will still see the Illusion, no matter how far away they are from the Zoroark.
The user must have seen the creature or object they wish to impersonate in person. Even the best videos and photos won't allow an Illusion master to impersonate their favorite celebrity; no resolution can emulate the detail and depth of real life.
Illusion is also able to copy inanimate objects, but it is extremely difficult to create a convincing copy, much less hold it for a period of time. The user must remain very still; even breathing too deeply can cause it to fail. Only the most skilled of users are able to pull off Illusions of non-animal subjects.
As appropriate odors are also part of the Illusion, this can also extend to emulate chemical smells such as perfume. However, imitating certain smells (such as chloroform) will not extend to the same neurological effects of the actual chemical compound (creating an Illusion of a chloroform-soaked rag will not knock anyone unconscious). Smell can still be a powerful deterrent, though; even an Illusion of a Muk can be quite nauseating!
The ability is not selective among its viewers. Everyone that looks upon the user sees the same Illusion. Electronic devices, sensors, and detection devices are not fooled by Illusions. As such, synthetic Pokemon and morphs are not fooled by Illusion as well - including the Porygon, Beldum, Magnemite, Klink, Honedge and Klefki lines, nor Genesect or Zygarde.
Illusion is broken when the user is damaged by any attack, or if the user's Ability is changed or nullified. It is not broken by Substitute, Life Orbs, weather conditions, status ailments or entry hazards.
Outside of battle, Illusion is able to able to survive everyday interaction with other people and objects - it won't be broken when squashed into a subway car, catching a thrown ball, or tripping on the sidewalk. However, it can be broken by high impact such as a punch or kick, or a car crash, or falling off a ladder; Illusion is also broken if the user falls asleep or unconscious.
Illusions that are of a greatly differing size from the user may also, at times, interact oddly. If a ball is thrown at a Zorua-Morph disguised as a much taller Onix-Morph, the ball will not actually interact with the Illusion of the Onix. With a very skilled Illusion user, the ball may have the appearance of bouncing off the Onix's head, but the physical ball would still pass through the Illusion and land behind the user. With Illusion users that have not fully mastered their skill, the ball may simply pass through the Illusion, like poor video game graphics! These incongruities can cause the Illusion to destabilize.