Essence of Antiquity

If a face-down spell leaves the stack and goes to any zone other than the battlefield (if it was countered, for example), you must reveal it. Similarly, if a face-down permanent leaves the battlefield, you must reveal it. You must also reveal all face-down spells and permanents you control if you leave the game or the game ends.

A permanent that turns face up or face down changes characteristics but is otherwise the same permanent. Spells and abilities that were targeting that permanent and Auras and Equipment that were attached to that permanent aren't affected unless the new characteristics of the object change the legality of those targets or attachments.

Turning a permanent face up or face down doesn't change whether that permanent is tapped or untapped.

If a face-down creature loses its abilities, it can't be turned face up with a disguise ability because it will no longer have a disguise ability (or a disguise cost) once face up.

A disguise ability lets you cast a card face down by paying {3} and announcing that you are using a disguise ability. Any time you have priority, you can turn a face-down permanent with disguise face up by paying its disguise cost.

Any time you have priority, you may turn the face-down creature face up by revealing what its disguise cost is and paying that cost. This is a special action. It doesn't use the stack and can't be responded to. Only a face-down permanent can be turned face up this way; a face-down spell cannot.

Because the permanent is on the battlefield both before and after it's turned face up, turning a permanent face up doesn't cause any enters-the-battlefield abilities to trigger.

At any time, you can look at a face-down spell or permanent you control. You can't look at face-down permanents or spells you don't control unless an effect instructs or allows you to do so.

Because face-down creatures don't have a name, they can't have the same name as any other creature, even another face-down creature.