What type of card is X?

X is a Legendary Creature — Human Spy. Its oracle text reads: "As long as X is in X's owner's opponent's hand, X's owner may cast X and activate X's abilities. That opponent can't cast X and plays with their hand revealed. {U}{B}, {T}: Put X into target opponent's hand. {3}{U}{B}: You may play a land or cast a spell from the hand X is in. If you cast a spell this way, you cast it without paying its mana cost."

X

Legendary Creature — Human Spy

As long as X is in X's owner's opponent's hand, X's owner may cast X and activate X's abilities. That opponent can't cast X and plays with their hand revealed.

, : Put X into target opponent's hand.