Altar of the Bloody Knife

Fortified land has "{t}, Sacrifice a creature: You gain life equal to the sacrificed creature's power."
Whenever fortified land becomes tapped, each opponent loses 1 life.
Fortify {1}{b}{b} ({1}{b}{b}: Attach to target land you control. Fortify only as a sorcery. This card enters the battlefield unattached and stays on the battlefield if the land leaves.)