Indemnification

Flying
Undying (When this creature dies, if it had no +1/+1 counters on it, return it to the battlefield under its owner's control with a +1/+1 counter on it.)
At the beginning of each player's upkeep, that player loses unless they shuffle X cards they own from any zone except their library into their library. X is equal to the number of counters on Indemnification.