Unlike a face-down creature that was cast using a disguise or morph ability, a cloaked creature may still be turned face up after it loses its abilities if it’s a creature card.
Unexplained Absence
Any time you have priority, you can turn a cloaked permanent you control face-up by revealing that it’s a creature card (ignoring any copy effects or type-changing effects that might be applying to it) and paying its mana cost. This is a special action. It doesn’t use the stack and can’t be responded to.
If something tries to turn a face-down instant or sorcery card on the battlefield face up, reveal that card to show all players it’s an instant or sorcery card. The permanent remains on the battlefield face down. Abilities that trigger when a permanent turns face up won’t trigger, because even though you revealed the card, it never turned face up.
Magic: The Gathering · ™ & © Wizards of the Coast · Illus. Rockey Chen
Card data via Scryfall. Rarix is fan-made; not endorsed by the rights holders.
