Creeping Frost

Creeping Frost enters the battlefield with seven
ice counters on it.
At the beginning of each player's end step, put a
tap counter on target land that player controls.
(It doesn't untap as long as it has a tap counter on it.)
{2}: Remove an ice counter from Creeping Frost,
then if there are no ice counters on it, it's
controller sacrifices it. Any player may activate
this ability.