Each player exiles all creature cards from their graveyard, then sacrifices all creatures they control, then puts all cards they exiled this way onto the battlefield.
When Mesmeric Fiend enters, target opponent reveals their hand and you choose a nonland card from it. Exile that card. When Mesmeric Fiend leaves the battlefield, return the exiled card to its owner's hand.
Skip your draw step. Whenever you discard a card, exile that card from your graveyard. Pay 1 life: Exile the top card of your library face down. Put that card into your hand at the beginning of your next end step.
Enchant creature When Paralyze enters, tap enchanted creature. Enchanted creature doesn't untap during its controller's untap step. At the beginning of the upkeep of enchanted creature's controller, that player may pay {4}. If the player does, untap the creature.
Discard a card: Putrid Imp gains flying until end of turn. Threshold — As long as seven or more cards are in your graveyard, Putrid Imp gets +1/+1 and can't block.
Sacrifice a creature, Return Recurring Nightmare to its owner's hand: Return target creature card from your graveyard to the battlefield. Activate only as a sorcery.
"I am confined by sleep and defined by nightmare." —Crovax
Each player sacrifices a creature of their choice. Create an X/X black Demon creature token with flying, where X is the total power of the creatures sacrificed this way.
When Sarcomancy enters, create a 2/2 black Zombie creature token. At the beginning of your upkeep, if there are no Zombies on the battlefield, Sarcomancy deals 1 damage to you.
Enchant creature Enchanted creature gets +3/+3. When enchanted creature becomes the target of a spell or ability, destroy that creature. It can't be regenerated.
"This one has not screamed enough to show effective implantation. Kill it." —Volrath
Will of the council — Starting with you, each player votes for death or torture. If death gets more votes, each opponent sacrifices a creature of their choice. If torture gets more votes or the vote is tied, each opponent loses 4 life.
Until end of turn, you may play lands and cast spells from your graveyard. If a card would be put into your graveyard from anywhere this turn, exile that card instead.