Flying

At the beginning of your upkeep, mill a card. If an instant or sorcery card was milled this way, transform Aberrant Researcher.

Flying

Whenever Abomination blocks or becomes blocked by a green or white creature, destroy that creature at end of combat.

When Abyssal Gatekeeper dies, each player sacrifices a creature.

Flying

When Abyssal Horror enters the battlefield, target player discards two cards.

Whenever an opponent discards a card, Abyssal Nocturnus gets +2/+2 and gains fear until end of turn. (It can't be blocked except by artifact creatures and/or black creatures.)

Flying

{2}{U}, Discard two cards: Return Advanced Stitchwing from your graveyard to the battlefield tapped.

{3}{U}: Ashiok's Skulker can't be blocked this turn.

+1: Create a 2/3 blue and black Nightmare creature token with "Whenever this creature attacks or blocks, each opponent exiles the top two cards of their library."

-3: Return target nonland permanent to its owner's hand, then that player exiles a card from their hand.

-7: You may cast up to three spells from among face-up cards your opponents own from exile without paying their mana costs.

+2: Exile the top three cards of target opponent's library.

-X: Put a creature card with mana value X exiled with Ashiok, Nightmare Weaver onto the battlefield under your control. That creature is a Nightmare in addition to its other types.

-10: Exile all cards from all opponents' hands and graveyards.

Lifelink, haste

Swampwalk (This creature can't be blocked as long as defending player controls a Swamp.)

When Blistergrub dies, each opponent loses 2 life.

Flying

Threshold -- As long as seven or more cards are in your graveyard, Boneshard Slasher gets +2/+2 and has "When Boneshard Slasher becomes the target of a spell or ability, sacrifice it."

Create a 1/1 blue and black Horror creature token with flying.

Cipher (Then you may exile this spell card encoded on a creature you control. Whenever that creature deals combat damage to a player, its controller may cast a copy of the encoded card without paying its mana cost.)

{2}, {T}: Search your library for a Mercenary permanent card with mana value 2 or less, put it onto the battlefield, then shuffle.

Fear (This creature can't be blocked except by artifact creatures and/or black creatures.)

{4}, {T}: Search your library for a Mercenary permanent card with mana value 4 or less, put it onto the battlefield, then shuffle.

Sacrifice a creature: Regenerate Cateran Overlord.

{6}, {T}: Search your library for a Mercenary permanent card with mana value 6 or less, put it onto the battlefield, then shuffle.

Swampwalk (This creature can't be blocked as long as defending player controls a Swamp.)

{5}, {T}: Search your library for a Mercenary permanent card with mana value 5 or less, put it onto the battlefield, then shuffle.

Mutate {3}{B} (If you cast this spell for its mutate cost, put it over or under target non-Human creature you own. They mutate into the creature on top plus all abilities from under it.)

Menace (This creature can't be blocked except by two or more creatures.)

Whenever this creature mutates, each opponent discards a card.

Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)

Chained Throatseeker can't attack unless defending player is poisoned.

All Nightmares get +1/+1.

{B}{B}{B}, Pay 3 life: Put target creature card from a graveyard onto the battlefield under your control. That creature is black and is a Nightmare in addition to its other creature types.

When Chainer, Dementia Master leaves the battlefield, exile all Nightmares.

Flying

Threshold -- As long as seven or more cards are in your graveyard, Childhood Horror gets +2/+2 and can't block.

Mutate {4}{B} (If you cast this spell for its mutate cost, put it over or under target non-Human creature you own. They mutate into the creature on top plus all abilities from under it.)

Whenever this creature mutates, each opponent sacrifices a creature.

Defender

{2}{B}: Transform Concealing Curtains. Activate only as a sorcery.

Menace

When this creature transforms into Revealing Eye, target opponent reveals their hand. You may choose a nonland card from it. If you do, that player discards that card, then draws a card.

Consuming Aberration's power and toughness are each equal to the number of cards in your opponents' graveyards.

Whenever you cast a spell, each opponent reveals cards from the top of their library until they reveal a land card, then puts those cards into their graveyard.

Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)

When Core Prowler dies, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

{1}{B}, Exile one or more creature cards from your graveyard: Create a tapped X/X black Zombie Horror creature token, where X is twice the number of cards exiled this way.

{B}, Sacrifice a creature: Regenerate Corrupted Harvester.

When Crypt Lurker enters the battlefield, you may sacrifice a creature or discard a creature card. If you do, draw a card.

Enchant player

As this permanent transforms into Curse of Leeches, attach it to a player.

At the beginning of enchanted player's upkeep, they lose 1 life and you gain 1 life.

Daybound (If a player casts no spells during their own turn, it becomes night next turn.)

Lifelink

Nightbound (If a player casts at least two spells during their own turn, it becomes day next turn.)

Flying

When Dark Hatchling enters the battlefield, destroy target nonblack creature. It can't be regenerated.

Shadow (This creature can block or be blocked by only creatures with shadow.)

Dauthi Horror can't be blocked by white creatures.

You may sacrifice three black creatures rather than pay this spell's mana cost.

Trample

Whenever one or more cards are put into your graveyard from your library, Devourer of Memory gets +1/+1 until end of turn and can't be blocked this turn.

{1}{U}{B}: Mill a card.

When Dinrova Horror enters the battlefield, return target permanent to its owner's hand, then that player discards a card.

Flying

Whenever you cast an instant or sorcery spell, create a 1/1 blue Human Wizard creature token. Then if you control three or more Wizards, transform Docent of Perfection.

Flying

Wizards you control get +2/+1 and have flying.

Whenever you cast an instant or sorcery spell, create a 1/1 blue Human Wizard creature token.

Whenever a Swamp enters the battlefield under your control, choose one --

• You draw a card and you lose 1 life.

• Dread Presence deals 2 damage to any target and you gain 2 life.

Whenever a creature dealt damage by Dread Slaver this turn dies, return it to the battlefield under your control. That creature is a black Zombie in addition to its other colors and types.

Landfall -- Whenever a land enters the battlefield under your control, Dreadwurm gains indestructible until end of turn. (Damage and effects that say "destroy" don't destroy it.)

When Drownyard Amalgam enters the battlefield, target player mills three cards. (They put the top three cards of their library into their graveyard.)

{2}{U}: Drownyard Amalgam can't be blocked this turn.

{0}: If Eater of the Dead is tapped, exile target creature card from a graveyard and untap Eater of the Dead.

When Enslaved Horror enters the battlefield, each other player may return a creature card from their graveyard to the battlefield.

Unearth {1}{U}{B} ({1}{U}{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.)

When Faceless Butcher enters the battlefield, exile target creature other than Faceless Butcher.

When Faceless Butcher leaves the battlefield, return the exiled card to the battlefield under its owner's control.

Commanders you control have menace and deathtouch.

Partner (You can have two commanders if both have partner.)

{B}: Fetid Horror gets +1/+1 until end of turn.

Transfigure {1}{B}{B} ({1}{B}{B}, Sacrifice this creature: Search your library for a creature card with the same mana value as this creature, put that card onto the battlefield, then shuffle. Transfigure only as a sorcery.)

Fear (This creature can't be blocked except by artifact creatures and/or black creatures.)

Threshold -- As long as seven or more cards are in your graveyard, Frightcrawler gets +2/+2 and can't block.

Sacrifice Fume Spitter: Put a -1/-1 counter on target creature.

Flying

Geralf's Masterpiece gets -1/-1 for each card in your hand.

{3}{U}, Discard three cards: Return Geralf's Masterpiece from your graveyard to the battlefield tapped.

When Geralf's Mindcrusher enters the battlefield, target player mills five cards.

Undying (When this creature dies, if it had no +1/+1 counters on it, return it to the battlefield under its owner's control with a +1/+1 counter on it.)

Whenever Gloom Sower becomes blocked by a creature, that creature's controller loses 2 life and you gain 2 life.

Menace

Evolve (Whenever a creature enters the battlefield under your control, if that creature has greater power or toughness than this creature, put a +1/+1 counter on this creature.)

When Gravegouger enters the battlefield, exile up to two target cards from a single graveyard.

When Gravegouger leaves the battlefield, return the exiled cards to their owner's graveyard.

Whenever a creature you control becomes blocked, you may return it to its owner's hand.

Whenever one or more creatures you control deal combat damage to a player, draw a card.

Grimdancer enters the battlefield with your choice of two different counters on it from among menace, deathtouch, and lifelink.

Fear (This creature can't be blocked except by artifact creatures and/or black creatures.)

Whenever Guiltfeeder attacks and isn't blocked, defending player loses 1 life for each card in their graveyard.

Whenever Havengul Skaab attacks, return another creature you control to its owner's hand.

{T}, Sacrifice a creature: Return target creature card from your graveyard to the battlefield. Activate only during your upkeep.

Hooded Horror can't be blocked as long as defending player controls the most creatures or is tied for the most.

Whenever you cycle or discard another card, Horror of the Broken Lands gets +2/+1 until end of turn.

Cycling {B} ({B}, Discard this card: Draw a card.)

{U}: Horror of the Dim gains hexproof until end of turn. (It can't be the target of spells or abilities your opponents control.)

{T}: Add {C}.

{1}, {T}, Sacrifice a creature: Put a soul counter on Hostile Hostel. Then if there are three or more soul counters on it, remove those counters, transform it, then untap it. Activate only as a sorcery.

Whenever Creeping Inn attacks, you may exile a creature card from your graveyard. If you do, each opponent loses X life and you gain X life, where X is the number of creature cards exiled with Creeping Inn.

{4}: Creeping Inn phases out.

Flash

This spell can't be countered.

Whenever you cast a spell, choose up to one --

• Return target spell you don't control to its owner's hand.

• Return target nonland permanent to its owner's hand.

Flying

When Hypnox enters the battlefield, if you cast it from your hand, exile all cards from target opponent's hand.

When Hypnox leaves the battlefield, return the exiled cards to their owner's hand.

Whenever Infectious Horror attacks, each opponent loses 2 life.

Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)

{U}: Ingenious Skaab gets +1/-1 until end of turn.

Mutate {2}{B} (If you cast this spell for its mutate cost, put it over or under target non-Human creature you own. They mutate into the creature on top plus all abilities from under it.)

Deathtouch

Whenever this creature mutates, each opponent loses X life and you gain X life, where X is the number of times this creature has mutated.

({B/P} can be paid with either {B} or 2 life.)

Lifelink

For each {B} in a cost, you may pay 2 life rather than pay that mana.

Whenever you cast a black spell, put a +1/+1 counter on K'rrik, Son of Yawgmoth.

At the beginning of each end step, draw a card if you've cast a spell from a graveyard or activated an ability of a card in a graveyard this turn.

Defender

{1}{U}: Put a hatchling counter on Ludevic's Test Subject. Then if there are five or more hatchling counters on it, remove all of them and transform it.

Trample

Whenever an opponent casts or copies an instant or sorcery spell, they lose 1 life.

When Mesmeric Fiend enters the battlefield, 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.

Dominate Monster -- When Mind Flayer enters the battlefield, gain control of target creature for as long as you control Mind Flayer.

Trample

Whenever Mindleech Mass deals combat damage to a player, you may look at that player's hand. If you do, you may cast a spell from among those cards without paying its mana cost.

Mutate {4}{B} (If you cast this spell for its mutate cost, put it over or under target non-Human creature you own. They mutate into the creature on top plus all abilities from under it.)

Flying

Whenever this creature mutates, exile the top card of each opponent's library face down. You may look at and play those cards for as long as they remain exiled.

Flying

Swampwalk (This creature can't be blocked as long as defending player controls a Swamp.)

Whenever Nemesis of Reason attacks, defending player mills ten cards.

When Netherborn Phalanx enters the battlefield, each opponent loses 1 life for each creature they control.

Transmute {1}{B}{B} ({1}{B}{B}, Discard this card: Search your library for a card with the same mana value as this card, reveal it, put it into your hand, then then shuffle. Transmute only as a sorcery.)

Bestow {2}{B}{B} (If you cast this card for its bestow cost, it's an Aura spell with enchant creature. It becomes a creature again if it's not attached to a creature.)

Nighthowler and enchanted creature each get +X/+X, where X is the number of creature cards in all graveyards.

Flying (This creature can't be blocked except by creatures with flying or reach.)

Nightmare's power and toughness are each equal to the number of Swamps you control.

Fear (This creature can't be blocked except by artifact creatures and/or black creatures.)

Suspend 7--{1}{B} (Rather than cast this card from your hand, you may pay {1}{B} and exile it with seven time counters on it. At the beginning of your upkeep, remove a time counter. When the last is removed, cast it without paying its mana cost. It has haste.)

Whenever a card is put into an opponent's graveyard from anywhere, if Nihilith is suspended, you may remove a time counter from Nihilith.

{2}{U}: Exile target creature card from your graveyard and put a +1/+1 counter on Patchwork Crawler.

Patchwork Crawler has all activated abilities of all creature cards exiled with it.

When you cast this spell, any player may discard three cards. If a player does, counter Phantasmagorian.

Discard three cards: Return Phantasmagorian from your graveyard to your hand.

When Phyrexian Gargantua enters the battlefield, you draw two cards and you lose 2 life.

Trample

Whenever a source deals damage to Phyrexian Obliterator, that source's controller sacrifices that many permanents.

When Phyrexian Rager enters the battlefield, you draw a card and you lose 1 life.

({B/P} can be paid with either {B} or 2 life.)

When Pith Driller enters the battlefield, put a -1/-1 counter on target creature.

Plague Mare can't be blocked by white creatures.

When Plague Mare enters the battlefield, creatures your opponents control get -1/-1 until end of turn.

Flying

Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)

{B}: Primeval Shambler gets +1/+1 until end of turn.

Two target players exchange life totals. You create an X/X colorless Horror artifact creature token, where X is the difference between those players' life totals.

Flying

When Psychic Symbiont enters the battlefield, target opponent discards a card and you draw a card.

When Rathi Fiend enters the battlefield, each player loses 3 life.

{3}, {T}: Search your library for a Mercenary permanent card with mana value 3 or less, put it onto the battlefield, then shuffle.

Fear (This creature can't be blocked except by artifact creatures and/or black creatures.)

{2}, {T}: Search your library for a Mercenary permanent card with mana value 2 or less, put it onto the battlefield, then shuffle.

When Ravenous Chupacabra enters the battlefield, destroy target creature an opponent controls.

Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)

Whenever a source deals damage to Reaper of Sheoldred, that source's controller gets a poison counter.

{1}{B}, {T}, Discard a card: Target creature gets +1/+0 and gains first strike until end of turn.

Roiling Horror's power and toughness are each equal to your life total minus the life total of an opponent with the most life.

Suspend X--{X}{B}{B}{B}. X can't be 0. (Rather than cast this card from your hand, you may pay {X}{B}{B}{B} and exile it with X time counters on it. At the beginning of your upkeep, remove a time counter. When the last is removed, cast it without paying its mana cost. It has haste.)

Whenever a time counter is removed from Roiling Horror while it's exiled, target player loses 1 life and you gain 1 life.

Flying

Whenever you attack with one or more creatures, target player mills that many cards. (To mill a card, a player puts the top card of their library into their graveyard.)

{2}{U}: Put Screaming Swarm from your graveyard into your library second from the top.

Lifelink (Damage dealt by this creature also causes you to gain that much life.)

As Sewer Nemesis enters the battlefield, choose a player.

Sewer Nemesis's power and toughness are each equal to the number of cards in the chosen player's graveyard.

Whenever the chosen player casts a spell, that player mills a card.

{3}{B}{B}: Monstrosity 3. (If this creature isn't monstrous, put three +1/+1 counters on it and it becomes monstrous.)

As long as Sinuous Vermin is monstrous, it has menace. (It can't be blocked except by two or more creatures.)

Flash

Whenever you cast another spell that has flash, you draw a card and each opponent loses 1 life.

Whenever Sludge Monster enters the battlefield or attacks, put a slime counter on up to one other target creature.

Non-Horror creatures with slime counters on them lose all abilities and have base power and toughness 2/2.

{U/P}: Change a target of target spell or ability to Spellskite. ({U/P} can be paid with either {U} or 2 life.)

Create an X/X black Horror creature token, where X is the number of creatures that died this turn.

Fear (This creature can't be blocked except by artifact creatures and/or black creatures.)

Target opponent mills thirteen cards.

{3}{U}{U}: Put Startled Awake from your graveyard onto the battlefield transformed. Activate only as a sorcery.

Skulk (This creature can't be blocked by creatures with greater power.)

When Persistent Nightmare deals combat damage to a player, return it to its owner's hand.

Stitched Mangler enters the battlefield tapped.

When Stitched Mangler enters the battlefield, tap target creature an opponent controls. That creature doesn't untap during its controller's next untap step.

Flying

{1}{U}, Discard two cards: Return Stitchwing Skaab from your graveyard to the battlefield tapped.

Swimmer in Nightmares gets +3/+0 as long as there are ten or more cards in a single graveyard.

Swimmer in Nightmares can't be blocked as long as you control an Ashiok planeswalker.

Defender

Thing in the Ice enters the battlefield with four ice counters on it.

Whenever you cast an instant or sorcery spell, remove an ice counter from Thing in the Ice. Then if it has no ice counters on it, transform it.

When this creature transforms into Awoken Horror, return all non-Horror creatures to their owners' hands.

Flying

Whenever Thrummingbird deals combat damage to a player, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

At the beginning of each end step, put a slime counter on each creature you don't control.

Creatures you don't control get -1/-1 for each slime counter on them.

Whenever a creature you don't control with a slime counter on it dies, create a 1/1 black Slug creature token.

{U}{B}, Sacrifice a Slug: Draw a card.

Umbris, Fear Manifest gets +1/+1 for each card your opponents own in exile.

Whenever Umbris or another Nightmare or Horror enters the battlefield under your control, target opponent exiles cards from the top of their library until they exile a land card.

Umbris, Fear Manifest gets +1/+1 for each card your opponents own in exile.

Whenever Umbris or another Nightmare or Horror enters the battlefield under your control, target opponent exiles cards from the top of their library until they exile a land card.

Umbris, Fear Manifest gets +1/+1 for each card your opponents own in exile.

Whenever Umbris or another Nightmare or Horror enters the battlefield under your control, target opponent exiles cards from the top of their library until they exile a land card.

Umbris, Fear Manifest gets +1/+1 for each card your opponents own in exile.

Whenever Umbris or another Nightmare or Horror enters the battlefield under your control, target opponent exiles cards from the top of their library until they exile a land card.

Deathtouch

Cycling {2}{B} ({2}{B}, Discard this card: Draw a card.)

When you cycle Void Beckoner, put a deathtouch counter on target creature you control.

Trample

If another creature would die, exile it instead.

Put a card exiled with Void Maw into its owner's graveyard: Void Maw gets +2/+2 until end of turn.

Skulk (This creature can't be blocked by creatures with greater power.)

Whenever Wharf Infiltrator deals combat damage to a player, you may draw a card. If you do, discard a card.

Whenever you discard a creature card, you may pay {2}. If you do, create a 3/2 colorless Eldrazi Horror creature token.

When Wretched Throng dies, you may search your library for a card named Wretched Throng, reveal it, put it into your hand, then shuffle.

When Yarok's Fenlurker enters the battlefield, each opponent exiles a card from their hand.

{2}{B}: Yarok's Fenlurker gets +1/+1 until end of turn.

Whenever this creature mutates, target creature an opponent controls gets -2/-2 until end of turn.