When Ovinomancer enters the battlefield, sacrifice it unless you return three basic lands you control to their owner's hand. {T}, Return Ovinomancer to its owner's hand: Destroy target creature. It can't be regenerated. That creature's controller creates a 0/1 green Sheep creature token.
Pirate Ship can't attack unless defending player controls an Island. {T}: Pirate Ship deals 1 damage to any target. When you control no Islands, sacrifice Pirate Ship.
Enchant creature Enchanted creature gets +3/+3. At the beginning of the upkeep of enchanted creature's controller, put a -1/-1 counter on that creature.
If there are ten or more creature cards total in all graveyards, this spell costs {6} less to cast. Fear {T}: Destroy target creature. It can't be regenerated.
As Conspiracy enters the battlefield, choose a creature type. Creatures you control are the chosen type. The same is true for creature spells you control and creature cards you own that aren't on the battlefield.
When Faceless Butcher enters the battlefield, exile another target creature. When Faceless Butcher leaves the battlefield, return the exiled card to the battlefield under its owner's control.
When Sengir Autocrat enters the battlefield, create three 0/1 black Serf creature tokens. When Sengir Autocrat leaves the battlefield, exile all Serf tokens.
"A thankless job, and a death sentence besides." —Eron the Relentless