Thanos, the Inevitable

Kicker: {2}{u}{b}{r}
When Thanos, the Inevitable enters the battlefield, choose one: If this spell was kicked, choose any number instead.
• Each opponent sacrifices half of the nonland permanents they control;
• Each opponent mills half their library rounded up;
• Thanos, the Inevitable deals damage to each player equal to the total power of creatures they control.