Disguise Kit

{x}{x}, {t}: You may put a creature card with
converted mana cost X or less from your hand
onto the battlefield face down as a 2/2 creature.
Put X mask counters on that creature. Activate
this ability only any time you could cast a sorcery.
The creature's controller may turn the creature
face up any time he or she could cast an instant
by removing all mask counters from it. This
effect ends if the creature is turned face up.