Soi Fon, Captain of the 2nd

Whenever Soi Fon deals combat damage to a
player, if they are marked for death, that player
loses the game unless they pay half of their life
rounded up. Otherwise, that player becomes
marked for death.
{1}{w/b}, Pay 2 life: Soi Fon gains your choice of
first strike or deathtouch until end of turn.