Aruthir, the Enigma Warden

Once per turn, whenever a player taps a land for
mana, if that land does not have a depletion
counter, put a depletion counter on it.
Lands with depletion counters on them don't
untap during their controller's untap step.
At the beginning of each player's upkeep, if there
are more lands with depletion counters than
untapped lands that player controls, that player sacrifices a land.Whenever a land with a
depletion counter on it is destroyed or exiled, its controller loses 1 life.