Le 3 septembre 2009, Wizards of the Coast a changé le texte d'Illusionary Mask (cf. Early September 2009 Update Bulletin ou ici).

Illusionary Mask
What a weird, weird card. Under the original rules in place for this card, a face-down creature is what it actually is … it was just face down. So, for example, if you had a face-down Lord of the Pit, and your opponent tried to Terror it (because how would she know it was black?) the Terror would be an illegal play. “It doesn't work.” “Why not?” “It just doesn't.” It would live through Infest. It would eat a creature during each of your upkeeps. This had some implementation problems, as you might imagine. Around the time the morph-filled Onslaught came out, the rules for face-down cards changed, and this card changed accordingly. But what it changed to was quite arbitrary, and didn't match what the card said at all.

The Oracle wording diverges pretty heavily from the printed wording. It ignored color considerations with the creature's mana cost (you originally had to pay the creature card's actual mana cost, plus whatever extra you wanted to disguise it), it put the creature directly onto the battlefield (you originally cast it), it used counters (which can be manipulated), and it allowed the creature to be turned face up whenever its controller wanted (such as when it's targeted with a -1/-1 ability), and it made the creature be 0/1 (which is imaginary; the printed card doesn't list a power and toughness because the creature was what it actually was).

There's no way we can mimic the original functionality; the rules regarding face-down creatures and hidden information are too strong and too logical. Instead, the card has been changed to come as close as possible to a modern-day interpretation (under the current rules system) of the printed card. This includes the notion that face-down creatures are 2/2, not 0/1.

New wording
{oX}: You may choose a creature card in your hand whose mana cost could be paid by some amount of, or all of, the mana you spent on {oX}. If you do, you may cast that card face down as a 2/2 creature spell without paying its mana cost. If the creature that spell becomes as it resolves has not been turned face up and would assign or deal damage, be dealt damage, or become tapped, instead it’s turned face up and assigns or deals damage, is dealt damage, or becomes tapped. Activate this ability only any time you could cast a sorcery.

There are memory issues involved. You need to write down and keep track of what was spent on {X} for each creature (including both amount and type of mana). Then later, when the card is turned face up, you can compare that mana to see if it included the creature's actual mana cost. If not, all appropriate punishments for cheating—given the game, the setting, and the sadisticness of one's opponents—apply.

C'est la fin de Vengeur Masqué:

• on peut contrer la créature
• on ne peut plus retourner la carte quand on veut
• il faut payer au moins le mana cost (les couleurs avec)

Avec le set Fate Reforged (Janvier 2015), une nouvelle abilité est intéressante : manifest

Manifest the top card of your library. (Put it on the battlefield face down as a 2/2 creature. Turn it face up any time for its mana cost if it's a creature card.)

On pourrait donc l'utiliser à la place d'Illusionary Mask, mais

• il faut que la carte se trouve au-dessus de la bibliothèque, donc utiliser
  • Brainstorm
  • Sylvan Library
  • Sensei's Divining Top
  • Enlightened Tutor (ou Worldly Tutor)

• Fate Reforged In Eternal, 12/01/2015

La seule carte potentielle est Cloudform

Enchantment, 1UU

When Cloudform enters the battlefield, it becomes an Aura with enchant creature. Manifest the top card of your library and attach Cloudform to it. (To manifest a card, put it onto the battlefield face down as a 2/2 creature. Turn it face up any time for its mana cost if it's a creature card.)

Enchanted creature has flying and hexproof.