X (Unstable 137) - Rare Magic: The Gathering Card

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.
: 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.