Acererak, Architect of Ruins

Acererak, Architect of Ruins' power is equal
to the number of completed dungeons.
(A dungeon may be completed multiple times.)
Whenever a creature attacks, it's controller
ventures into the dungeon.
Whenever a player completes a dungeon, it's
controller loses life equal to Acererak, Architect
of Ruins' power and sacrifices a creature.