Worst Fears

You control target player during that player's next turn. Exile Worst Fears. (You see all cards that player could see and make all decisions for the player.)

Quest for Ula's Temple

At the beginning of your upkeep, you may look at the top card of your library. If it's a creature card, you may reveal it and put a quest counter on Quest for Ula's Temple.
At the beginning of each end step, if there are three or more quest counters on Quest for Ula's Temple, you may put a Kraken, Leviathan, Octopus, or Serpent creature card from your hand onto the battlefield.

Deepfathom Skulker

Devoid (This card has no color.)
Whenever a creature you control deals combat damage to a player, you may draw a card.
{3}{C}: Target creature can't be blocked this turn. ({C} represents colorless mana.)

Colossal Whale

Islandwalk (This creature can't be blocked as long as defending player controls an Island.)
Whenever Colossal Whale attacks, you may exile target creature defending player controls until Colossal Whale leaves the battlefield. (That creature returns under its owner's control.)

Krothuss, Lord of the Deep

Flying
Whenever Krothuss, Lord of the Deep attacks, create a tapped and attacking token that's a copy of another target attacking creature. If that creature is a Kraken, Leviathan, Octopus, or Serpent, create two of those tokens instead.

Runo Stromkirk

Flying
When Runo Stromkirk enters the battlefield, put up to one target creature card from your graveyard on top of your library.
At the beginning of your upkeep, look at the top card of your library. You may reveal that card. If a creature card with mana value 6 or greater is revealed this way, transform Runo Stromkirk.

Runo Stromkirk // Krothuss, Lord of the Deep

Slinn Voda, the Rising Deep

Kicker {1}{U} (You may pay an additional {1}{U} as you cast this spell.)
When Slinn Voda, the Rising Deep enters the battlefield, if it was kicked, return all creatures to their owners' hands except for Merfolk, Krakens, Leviathans, Octopuses, and Serpents.

Lorthos, the Tidemaker

Whenever Lorthos, the Tidemaker attacks, you may pay {8}. If you do, tap up to eight target permanents. Those permanents don't untap during their controllers' next untap steps.

Ponder

Look at the top three cards of your library, then put them back in any order. You may shuffle.
Draw a card.

Darksteel Plate

Indestructible
Equipped creature has indestructible.
Equip {2}

Spawning Kraken

Whenever a Kraken, Leviathan, Octopus, or Serpent you control deals combat damage to a player, create a 9/9 blue Kraken creature token.

Thassa, Deep-Dwelling

Indestructible
As long as your devotion to blue is less than five, Thassa isn't a creature.
At the beginning of your end step, exile up to one other target creature you control, then return that card to the battlefield under your control.
{3}{U}: Tap another target creature.

Mysteries of the Deep

Draw two cards.
Landfall — If you had a land enter the battlefield under your control this turn, draw three cards instead.

The Watcher in the Water

The Watcher in the Water enters the battlefield tapped with nine stun counters on it. (If a permanent with a stun counter would become untapped, remove one from it instead.)
Whenever you draw a card during an opponent's turn, create a 1/1 blue Tentacle creature token.
Whenever a Tentacle you control dies, untap up to one target Kraken and put a stun counter on up to one target nonland permanent.

Drowned Catacomb

Drowned Catacomb enters the battlefield tapped unless you control an Island or a Swamp.
{T}: Add {U} or {B}.

Fleet Swallower

Whenever Fleet Swallower attacks, target player mills half their library, rounded up.

Marvo, Deep Operative

Whenever Marvo, Deep Operative attacks, clash with defending player. (Each clashing player reveals the top card of their library, then puts that card on the top or bottom. A player wins if their card had a higher mana value.)
Whenever you win a clash, draw a card. Then you may cast a spell from your hand with mana value 8 or less without paying its mana cost.

Fish

When this creature dies, create a 6/6 blue Whale creature token with "When this creature dies, create a 9/9 blue Kraken creature token."

Dimir Guildgate

Dimir Guildgate enters the battlefield tapped.
{T}: Add {U} or {B}.

Tidal Kraken

Copy

(This token can be used to represent a token that's a copy of a permanent.)

Morphic Pool

Morphic Pool enters the battlefield tapped unless you have two or more opponents.
{T}: Add {U} or {B}.

Worn Powerstone

Worn Powerstone enters the battlefield tapped.
{T}: Add {C}{C}.

Ominous Seas

Whenever you draw a card, put a foreshadow counter on Ominous Seas.
Remove eight foreshadow counters from Ominous Seas: Create an 8/8 blue Kraken creature token.
Cycling {2} ({2}, Discard this card: Draw a card.)

Drown in the Loch

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.

Creeping Tar Pit

Creeping Tar Pit enters the battlefield tapped.
{T}: Add {U} or {B}.
{1}{U}{B}: Creeping Tar Pit becomes a 3/2 blue and black Elemental creature until end of turn and can't be blocked this turn. It's still a land.

Star Whale

Flying, vigilance
Other creatures you control have ward {2}.
Suspend 6—{1}{U} (Rather than cast this card from your hand, you may pay {1}{U} and exile it with six time counters on it. At the beginning of your upkeep, remove a time counter. When the last is removed, you may cast it without paying its mana cost. It has haste.)

Jace's Mindseeker

Flying
When Jace's Mindseeker enters the battlefield, target opponent mills five cards. You may cast an instant or sorcery spell from among them without paying its mana cost.

Weed Strangle

Destroy target creature. Clash with an opponent. If you win, you gain life equal to that creature's toughness. (Each clashing player reveals the top card of their library, then puts that card on the top or bottom. A player wins if their card had a higher mana value.)

Coldsteel Heart

Coldsteel Heart enters the battlefield tapped.
As Coldsteel Heart enters the battlefield, choose a color.
{T}: Add one mana of the chosen color.

Temple of Deceit

Temple of Deceit enters the battlefield tapped.
When Temple of Deceit enters the battlefield, scry 1.
{T}: Add {U} or {B}.

Memory Plunder

You may cast target instant or sorcery card from an opponent's graveyard without paying its mana cost.

Aminatou's Augury

Exile the top eight cards of your library. You may put a land card from among them onto the battlefield. Until end of turn, for each nonland card type, you may cast a spell of that type from among the exiled cards without paying its mana cost.

Tunnel Vision

Choose a card name. Target player reveals cards from the top of their library until a card with that name is revealed. If it is, that player puts the rest of the revealed cards into their graveyard and puts the card with the chosen name on top of their library. Otherwise, the player shuffles.

Awoken Horror

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

Thing in the Ice

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.

Thing in the Ice // Awoken Horror

Kederekt Leviathan

When Kederekt Leviathan enters the battlefield, return all other nonland permanents to their owners' hands.
Unearth {6}{U} ({6}{U}: 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.)

Caged Sun

As Caged Sun enters the battlefield, choose a color.
Creatures you control of the chosen color get +1/+1.
Whenever a land's ability causes you to add one or more mana of the chosen color, add one additional mana of that color.

Shipwreck Marsh

Shipwreck Marsh enters the battlefield tapped unless you control two or more other lands.
{T}: Add {U} or {B}.

Myriad Landscape

Myriad Landscape enters the battlefield tapped.
{T}: Add {C}.
{2}, {T}, Sacrifice Myriad Landscape: Search your library for up to two basic land cards that share a land type, put them onto the battlefield tapped, then shuffle.

Darkwater Catacombs

Monstrosity of the Lake

When Monstrosity of the Lake enters the battlefield, you may pay {5}. If you do, tap all creatures your opponents control, then put a stun counter on each of those creatures. (If a permanent with a stun counter would become untapped, remove one from it instead.)
Islandcycling {2} ({2}, Discard this card: Search your library for an Island card, reveal it, put it into your hand, then shuffle.)

Kraken

Roaming Throne

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.

Sunken Hollow

({T}: Add {U} or {B}.)
Sunken Hollow enters the battlefield tapped unless you control two or more basic lands.

Commander's Sphere

{T}: Add one mana of any color in your commander's color identity.
Sacrifice Commander's Sphere: Draw a card.

Scourge of Fleets

When Scourge of Fleets enters the battlefield, return each creature your opponents control with toughness X or less to its owner's hand, where X is the number of Islands you control.

Captivating Glance

Enchant creature
At the beginning of your end step, clash with an opponent. If you win, gain control of enchanted creature. Otherwise, that player gains control of enchanted creature. (Each clashing player reveals the top card of their library, then puts that card on the top or bottom. A player wins if their card had a higher mana value.)

Lightning Greaves

Equipped creature has haste and shroud. (It can't be the target of spells or abilities.)
Equip {0}

Restless Reef

Restless Reef enters the battlefield tapped.
{T}: Add {U} or {B}.
{2}{U}{B}: Until end of turn, Restless Reef becomes a 4/4 blue and black Shark creature with deathtouch. It's still a land.
Whenever Restless Reef attacks, target player mills four cards.

Voracious Greatshark

Flash
When Voracious Greatshark enters the battlefield, counter target artifact or creature spell.

Fellwar Stone

{T}: Add one mana of any color that a land an opponent controls could produce.

Undercity Sewers

({T}: Add {U} or {B}.)
Undercity Sewers enters the battlefield tapped.
When Undercity Sewers enters the battlefield, surveil 1. (Look at the top card of your library. You may put it into your graveyard.)

Whelming Wave

Return all creatures to their owners' hands except for Krakens, Leviathans, Octopuses, and Serpents.

Sinister Starfish

{T}: Surveil 1. (Look at the top card of your library. You may put it into your graveyard.)

Nezahal, Primal Tide

This spell can't be countered.
You have no maximum hand size.
Whenever an opponent casts a noncreature spell, draw a card.
Discard three cards: Exile Nezahal, Primal Tide. Return it to the battlefield tapped under its owner's control at the beginning of the next end step.

Sea-Dasher Octopus

Mutate {1}{U} (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.)
Flash
Whenever this creature deals combat damage to a player, draw a card.

Gilded Lotus

Diluvian Primordial

Flying
When Diluvian Primordial enters the battlefield, for each opponent, you may cast up to one target instant or sorcery card from that player's graveyard without paying its mana cost. If a spell cast this way would be put into a graveyard, exile it instead.

Lantern of Insight

Players play with the top card of their libraries revealed.
{T}, Sacrifice Lantern of Insight: Target player shuffles.

The Reality Chip

You may look at the top card of your library any time.
As long as The Reality Chip is attached to a creature, you may play lands and cast spells from the top of your library.
Reconfigure {2}{U} ({2}{U}: Attach to target creature you control; or unattach from a creature. Reconfigure only as a sorcery. While attached, this isn't a creature.)

Halimar Depths

Halimar Depths enters the battlefield tapped.
When Halimar Depths enters the battlefield, look at the top three cards of your library, then put them back in any order.
{T}: Add {U}.

Spark Double

You may have Spark Double enter the battlefield as a copy of a creature or planeswalker you control, except it enters with an additional +1/+1 counter on it if it's a creature, it enters with an additional loyalty counter on it if it's a planeswalker, and it isn't legendary.

Gyruda, Doom of Depths

Companion — Your starting deck contains only cards with even mana values. (If this card is your chosen companion, you may put it into your hand from outside the game for {3} as a sorcery.)
When Gyruda enters the battlefield, each player mills four cards. Put a creature card with an even mana value from among the milled cards onto the battlefield under your control.

Research the Deep

Draw a card. Clash with an opponent. If you win, return Research the Deep to its owner's hand. (Each clashing player reveals the top card of their library, then puts that card on the top or bottom. A player wins if their card had a higher mana value.)

Mana Crypt

At the beginning of your upkeep, flip a coin. If you lose the flip, Mana Crypt deals 3 damage to you.
{T}: Add {C}{C}.

Lagoon Breach

The owner of target attacking creature you don't control puts it on the top or bottom of their library.

Horned Loch-Whale

Flash
Ward {2}
Horned Loch-Whale enters the battlefield tapped unless it's your turn.

Horned Loch-Whale // Lagoon Breach

Command Tower

{T}: Add one mana of any color in your commander's color identity.

Benthic Anomaly

Devoid
When you cast this spell, for each opponent, choose a creature that player controls. Create a token that's a copy of one of those creatures, except its power is equal to the total power of those creatures, its toughness is equal to the total toughness of those creatures, and it's a colorless Eldrazi creature.

Denizen of the Deep

When Denizen of the Deep enters the battlefield, return each other creature you control to its owner's hand.

Sleep with the Fishes

Enchant creature
When Sleep with the Fishes enters the battlefield, tap enchanted creature and you create a 1/1 blue Fish creature token with "This creature can't be blocked."
Enchanted creature doesn't untap during its controller's untap step.

Reliquary Tower

You have no maximum hand size.
{T}: Add {C}.

Arcane Signet

Stormtide Leviathan

Islandwalk (This creature can't be blocked as long as defending player controls an Island.)
All lands are Islands in addition to their other types.
Creatures without flying or islandwalk can't attack.

Dimir Aqueduct

Dimir Aqueduct enters the battlefield tapped.
When Dimir Aqueduct enters the battlefield, return a land you control to its owner's hand.
{T}: Add {U}{B}.

Trench Behemoth

Return a land you control to its owner's hand: Untap Trench Behemoth. It gains hexproof until end of turn.
Landfall — Whenever a land enters the battlefield under your control, target creature an opponent controls attacks during its controller's next combat phase if able.

Great Whale

When Great Whale enters the battlefield, untap up to seven lands.

Reef Worm

When Reef Worm dies, create a 3/3 blue Fish creature token with "When this creature dies, create a 6/6 blue Whale creature token with 'When this creature dies, create a 9/9 blue Kraken creature token.'"

Extract from Darkness

Each player mills two cards. Then you put a creature card from a graveyard onto the battlefield under your control.

Spectral Deluge

Return each creature your opponents control with toughness X or less to its owner's hand, where X is the number of Islands you control.
Foretell {1}{U}{U} (During your turn, you may pay {2} and exile this card from your hand face down. Cast it on a later turn for its foretell cost.)

Stormsurge Kraken

Hexproof
Lieutenant — As long as you control your commander, Stormsurge Kraken gets +2/+2 and has "Whenever Stormsurge Kraken becomes blocked, you may draw two cards."

Swiftfoot Boots

Equipped creature has hexproof and haste. (It can't be the target of spells or abilities your opponents control.)
Equip {1}

Wrexial, the Risen Deep

Islandwalk, swampwalk (This creature can't be blocked as long as defending player controls an Island or a Swamp.)
Whenever Wrexial, the Risen Deep deals combat damage to a player, you may cast target instant or sorcery card from that player's graveyard without paying its mana cost. If that spell would be put into a graveyard, exile it instead.

Hullbreaker Horror

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.

Revive the Fallen

Return target creature card from a graveyard to its owner's hand. Clash with an opponent. If you win, return Revive the Fallen to its owner's hand. (Each clashing player reveals the top card of their library, then puts that card on the top or bottom. A player wins if their card had a higher mana value.)

Collector's Vault

{2}, {T}: Draw a card, then discard a card. Create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

Island

Aboleth Spawn

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.

Kenessos, Priest of Thassa

If you would scry a number of cards, scry that many cards plus one instead.
{3}{G/U}: Look at the top card of your library. If it's a Kraken, Leviathan, Octopus, or Serpent creature card, you may put it onto the battlefield. If you don't put the card onto the battlefield, you may put it on the bottom of your library.

Sol Ring

Darkslick Shores

Darkslick Shores enters the battlefield tapped unless you control two or fewer other lands.
{T}: Add {U} or {B}.

Dimir Signet

Shark Typhoon

Whenever you cast a noncreature spell, create an X/X blue Shark creature token with flying, where X is that spell's mana value.
Cycling {X}{1}{U} ({X}{1}{U}, Discard this card: Draw a card.)
When you cycle Shark Typhoon, create an X/X blue Shark creature token with flying.

Shark

Vesuvan Drifter

Flying
You may look at the top card of your library any time.
At the beginning of each combat, you may reveal the top card of your library. If you reveal a creature card this way, Vesuvan Drifter becomes a copy of that card until end of turn, except it has flying.

Myojin of Cryptic Dreams

Myojin of Cryptic Dreams enters the battlefield with an indestructible counter on it if you cast it from your hand.
Remove an indestructible counter from Myojin of Cryptic Dreams: Copy target permanent spell you control three times. (The copies become tokens.)

Tromokratis

Tromokratis has hexproof unless it's attacking or blocking.
Tromokratis can't be blocked unless all creatures defending player controls block it. (If any creature that player controls doesn't block this creature, it can't be blocked.)

Brinelin, the Moon Kraken

When Brinelin, the Moon Kraken enters the battlefield or whenever you cast a spell with mana value 6 or greater, you may return target nonland permanent to its owner's hand.
Partner (You can have two commanders if both have partner.)

Elder Deep-Fiend

Flash
Emerge {5}{U}{U} (You may cast this spell by sacrificing a creature and paying the emerge cost reduced by that creature's mana value.)
When you cast this spell, tap up to four target permanents.

Demonic Tutor

Search your library for a card, put that card into your hand, then shuffle.

Scattering Stroke

Counter target spell. Clash with an opponent. If you win, at the beginning of your next main phase, you may add an amount of {C} equal to that spell's mana value. (Each clashing player reveals the top card of their library, then puts that card on the top or bottom. A player wins if their card had a higher mana value.)

Three Steps Ahead

Spree (Choose one or more additional costs.)
+ {1}{U} — Counter target spell.
+ {3} — Create a token that's a copy of target artifact or creature you control.
+ {2} — Draw two cards, then discard a card.

Serpent of Yawning Depths

Krakens, Leviathans, Octopuses, and Serpents you control can't be blocked except by Krakens, Leviathans, Octopuses, and Serpents.