The Snap

For each creature on the battlefield, flip a coin. If the coin lands on heads, exile that creature. Repeat this process for each creature in each players hand, graveyard, and library.
For each player, flip a coin. If that coin lands on heads, that player loses the game. Your life total can't change during your next turn.
"When I am done, half of humanity will still exist. Perfectly balanced, as all things should be. I hope they remember you." -Thanos