707.1.
Two cards (Illusionary Mask and Ixidron) and the morph ability (see rule 702.35) allow spells
and permanents to be face down.
707.2.
Face-down spells and face-down permanents have no characteristics other than those listed by
the ability or rules that allowed the spell or permanent to be face down. Any listed characteristics
are the copiable values of that object‘s characteristics. (See rule 613, «Interaction of Continuous
Effects,» and rule 706, «Copying Objects.»)
707.2a
If a face-up permanent is turned face down by a spell or ability, it becomes a 2/2 face-down
creature with no text, no name, no subtypes, no expansion symbol, and no mana cost. These
values are the copiable values of that object‘s characteristics.
707.3.
Objects that are put onto the battlefield face down are turned face down before they enter the
battlefield, so the permanent‘s enters-the-battlefield abilities won‘t trigger (if triggered) or have any
effect (if static).
707.4.
Objects that are cast face down are turned face down before they are put onto the stack, so
effects that care about the characteristics of a spell will see only the face-down spell‘s
characteristics. Any effects or prohibitions that would apply to casting an object with these
characteristics (and not the face-up object‘s characteristics) are applied to casting this object. The
permanent the spell becomes will be a face-down permanent.
707.5.
At any time, you may look at a face-down spell you control on the stack or a face-down
permanent you control (even if it‘s phased out). You can‘t look at face-down cards in any other
zone or face-down spells or permanents controlled by another player.
707.6.
If you control multiple face-down spells or face-down permanents, you must ensure at all times
that your face-down spells and permanents can be easily differentiated from each other. This
includes, but is not limited to, knowing the order spells were cast, the order that face-down
permanents entered the battlefield, which creature attacked last turn, and any other differences
between face-down spells or permanents. Common methods for distinguishing between face-down
objects include using counters or dice to mark the different objects, or clearly placing those objects
in order on the table.
707.7.
The ability or rules that allow a permanent to be face down may also allow the permanent‘s
controller to turn it face up. Spells normally can‘t be turned face up.
707.8.
As a face-down permanent is turned face up, its copiable values revert to its normal copiable
values. Any effects that have been applied to the face-down permanent still apply to the face-up
permanent. Any abilities relating to the permanent entering the battlefield don‘t trigger and don‘t
have any effect, because the permanent has already entered the battlefield.
707.9.
If a face-down permanent moves from the battlefield to any other zone, its owner must reveal it
to all players as he or she moves it. If a face-down spell moves from the stack to any zone other
than the battlefield, its owner must reveal it to all players as he or she moves it. At the end of each
game, all face-down permanents and spells must be revealed to all players.
707.10.
If a face-down permanent becomes a copy of another permanent, its copiable values become
the copiable values of that permanent, as modified by its face-down status. Its characteristics
therefore remain the same: the characteristics listed by the ability or rules that allowed it to be
turned face down. However, if it is turned face up, its copiable values become the values it copied
from the other permanent. See rule 706.3.
707.11.
If a face-down permanent would have an «As [this permanent] is turned face up . . .» ability
after it‘s turned face up, that ability is applied while that permanent is being turned face up, not
afterward.