Final Light

You and target opponent's life totals become 50.
Until end of turn, creatures you control have
lifelink. This turn, whenever you cast a spell,
attack with a creature, or activate an ability
that isn't a mana ability, gain 2 life. At the
beginning of the next end step, if you have 100
or more life, you win the game. Otherwise the
chosen opponent wins the game.
Ultimatum (You may not cast more than one spell
with Ultimatum per game. Spells with Ultimatum
cannot be copied.)