Flash

Ward {2}

Probing Telepathy -- Whenever a creature entering the battlefield under an opponent's control causes a triggered ability of that creature to trigger, you may copy that ability. You may choose new targets for the copy.

Flying

At the beginning of your end step, exile the top card of each opponent's library. You may play those cards for as long as they remain exiled. If you cast a spell this way, you may spend mana as though it were mana of any color to cast it.

Whenever a nonland permanent an opponent owns enters the battlefield under your control, they lose life equal to its mana value.

Horrors you control have menace.

Whenever a Horror you control deals combat damage to a player, that player mills that many cards.

At the beginning of your end step, choose target artifact or creature card in an opponent's graveyard that was put there from their library this turn. Put it onto the battlefield under your control.

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.

Choose one --

• Counter target spell with mana value less than or equal to the number of cards in its controller's graveyard.

• Destroy target creature with mana value less than or equal to the number of cards in its controller's graveyard.

Enchant creature you control

At the beginning of your upkeep, create a token that's a copy of enchanted creature, except the token is 1/1.

When enchanted creature dies, if that creature was a Horror, return Endless Evil to its owner's hand.

Each opponent mills fourteen cards.

Cycling {1}{U} ({1}{U}, Discard this card: Draw a card.)

When you cycle Fractured Sanity, each opponent mills four cards.

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.

Aberrant Tinkering -- When Grell Philosopher enters the battlefield and at the beginning of your upkeep, each Horror you control gains all activated abilities of target artifact an opponent controls until end of turn. You may spend blue mana as though it were mana of any color to activate those abilities.

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.

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.

Equipped creature has haste and shroud. (It can't be the target of spells or abilities.)

Equip {0}

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

Whenever an opponent loses life, that player mills that many cards. (Damage causes loss of life.)

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

Each creature gets twice -X/-X until end of turn. Each player gets X rad counters.

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

Exile target nonland card in a graveyard that was put there from anywhere this turn. Copy it. You may cast the copy without paying its mana cost.

Ward {2}

As Roaming Throne enters the battlefield, choose a creature type.

Roaming Throne is the chosen type in addition to its other types.

If a triggered ability of another creature you control of the chosen type triggers, it triggers an additional time.

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.

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.

Descend 8 -- The Ancient One can't attack or block unless there are eight or more permanent cards in your graveyard.

{2}{U}{B}: Draw a card, then discard a card. When you discard a card this way, target player mills cards equal to its mana value.

As an additional cost to cast this spell, pay X life.

All creatures get -X/-X until end of turn.

Uchuulon's power is equal to the number of Crabs, Oozes, and/or Horrors you control.

Horrific Symbiosis -- At the beginning of your end step, exile up to one target creature card from an opponent's graveyard. If you do, create a token that's a copy of Uchuulon.

Hive Mind -- Whenever a player mills one or more creature cards, you create a 1/1 black Horror creature token.

{1}, {T}: Target player mills three cards.

Choose a Background (You can have a Background as a second commander.)