Leonin Shape-Mage

When Leonin Shape-Mage enters the battlefield, choose another Cat creature card from outside the game. Leonin Shape-Mage becomes a copy of that card, except it is still white and blue and is still called Leonin Shape-Mage.
When Leonin Shape-Mage dies, choose target creature you control and sacrifice that creature. Then return Leonin Shape-Mage from your graveyard to the battlefield.
You can't choose a card from outside the game more than once each game.