Seize the Moment

Take an extra turn after this one. At the beginning of that turn's upkeep, gain control of target creature until end of turn. Untap it. It gains haste until end of turn. At the beginning of that turn's end step, you lose the game.
"Tiamat, right? Listen, Amiriva's dead, Saldur's dead, the cleric - I never learned his name - is dead, even my buddy Salazar's dead. Now, I want to die with a story. Wha