Oberyn Martell, the Red Viper

When Oberyn Martell, the Red Viper enters the battlefield, chose targed creature an oponnent controls. When that creature leaves the battlefield, you win the game.
If Oberyn Martell leaves the battlefield, you lose the game.
"I am going to hear you confess before you die." -Oberyn Martell, the Red Viper
I am going to hear you confess before you die