Curse of the Final Hour

When Curse of the Final Hour enters the battlefield, put seven doom counters on it.
Whever a creature would be sent to a graveyard from the battlefield, exile it instead and remove a doom counter from Curse of the Final Hour. If you cannot, instead sacrifice Curse of the Final Hour and return up to seven creatures from exile onto the battlefield under your control.
Death is but the fuel ... ... of apocalypse.