Sacrifice a creature: Target player mills cards equal to the sacrificed creature's power.

Sacrifice a creature: Add {C}{C}.

Flying When this creature enters, create a number of 1/1 black Harpy creature tokens with flying equal to your devotion to black. (Each {B} in the mana costs of permanents you control counts toward your devotion to black.) At the beginning of your upkeep, sacrifice a creature.

Flying Whenever another creature leaves the battlefield, you may have target player mill two cards. Unearth {2}{B} ({2}{B}: Return this card from your graveyard to the battlefield. It gains haste. Exile it at the beginning of the next end step or if it would leave the battlefield. Unearth only as a sorcery.)

Flying, trample Whenever an opponent searches their library, that player sacrifices a creature of their choice and loses 10 life. Whenever another creature dies, put a +1/+1 counter on Ob Nixilis.

Flying, trample Pay 2 life, Sacrifice another creature: Search your library for a card, put that card into your hand, then shuffle.

This land enters tapped. When this land enters, exile target player's graveyard. {T}: Add {B}.

{2}, {T}: Add {B} for each Swamp you control.

This land enters tapped. {T}: Add {B}. {2}, {T}: Add {B} for each black creature card in your graveyard.