Death's Hourglass

Hexproof
When Death's Hourglass enters the battlefield,
choose any number larger than 20. Put that
many time counters on Death's Hourglass.
Whenever a player draws any number of cards,
or any number of lands are tapped for mana,
remove a number of time counters from Death's Hourglass equal to the cards drawn of lands
tapped. Then, if there are no counters remaining,
each player sacrifices all their nonland
permanents, then end the turn.