Nihilox, the Voidshaper

At the beginning of each player's upkeep, that
player sacrifices a nonland permanent unless
they pay X, where X is equal to the number of permanents they control.
Whenever a permanent is sacrificed, its
controller loses life equal to its converted mana
cost.
"In the realm of Nihilox, all that is cherished will
crumble to dust, consumed by the unyielding void."