Krimux, Mineshaft Worker

At the beginning of your upkeep, each opponent
gains a damage counter.
Whenever an opponent decides to take damage
from damage counters, you may destroy a land
and/or an artifact they control.
Damage Counters- At the beginning of each end step,
if a player has damage counters, they may choose to
take 2 damage for each damage counter and lose all
damage counters. Then, if they have 21 or more
damage counters, they lose the game.