Flying

{2}{U}, Discard a card: Return Amugaba to its owner's hand.

Islandwalk (This creature can't be blocked as long as defending player controls an Island.)

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.)

Trample

At the beginning of your upkeep, sacrifice Deep Spawn unless you mill two cards.

{U}: Deep Spawn gains shroud until end of turn and doesn't untap during your next untap step. Tap Deep Spawn. (A creature with shroud can't be the target of spells or abilities.)

Deep-Sea Kraken can't be blocked.

Suspend 9--{2}{U} (Rather than cast this card from your hand, you may pay {2}{U} and exile it with nine 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 an opponent casts a spell, if Deep-Sea Kraken is suspended, remove a time counter from it.

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

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

Flying, trample

When Eater of Days enters the battlefield, you skip your next two turns.

At the beginning of your upkeep, unless you sacrifice an Island, sacrifice Elder Spawn and it deals 6 damage to you.

Elder Spawn can't be blocked by red creatures.

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

Defender (This creature can't attack.)

When Grozoth enters the battlefield, you may search your library for any number of cards that have mana value 9, reveal them, put them into your hand, then shuffle.

{4}: Grozoth loses defender until end of turn.

Transmute {1}{U}{U} ({1}{U}{U}, 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 shuffle. Transmute only as a sorcery.)

Trample

Islandwalk (This creature can't be blocked as long as defending player controls an Island.)

Shroud (This creature can't be the target of spells or abilities.)

Island Fish Jasconius doesn't untap during your untap step.

At the beginning of your upkeep, you may pay {U}{U}{U}. If you do, untap Island Fish Jasconius.

Island Fish Jasconius can't attack unless defending player controls an Island.

When you control no Islands, sacrifice Island Fish Jasconius.

Trample

Jokulmorder enters the battlefield tapped.

When Jokulmorder enters the battlefield, sacrifice it unless you sacrifice five lands.

Jokulmorder doesn't untap during your untap step.

Whenever you play an Island, you may untap Jokulmorder.

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.)

Flying

When Keiga, the Tide Star dies, gain control of target creature.

Trample

Leviathan enters the battlefield tapped and doesn't untap during your untap step.

At the beginning of your upkeep, you may sacrifice two Islands. If you do, untap Leviathan.

Leviathan can't attack unless you sacrifice two Islands. (This cost is paid as attackers are declared.)

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.

Marjhan doesn't untap during your untap step.

{U}{U}, Sacrifice a creature: Untap Marjhan. Activate only during your upkeep.

Marjhan can't attack unless defending player controls an Island.

{U}{U}: Marjhan gets -1/-0 until end of turn and deals 1 damage to target attacking creature without flying.

When you control no Islands, sacrifice Marjhan.

Trample

Polar Kraken enters the battlefield tapped.

Cumulative upkeep--Sacrifice a land. (At the beginning of your upkeep, put an age counter on this permanent, then sacrifice it unless you pay its upkeep cost for each age counter on it.)

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.

Sea Monster can't attack unless defending player controls an Island.

Sea Serpent can't attack unless defending player controls an Island.

When you control no Islands, sacrifice Sea Serpent.

{6}{U}{U}: Monstrosity 4. (If this creature isn't monstrous, put four +1/+1 counters on it and it becomes monstrous.)

When Shipbreaker Kraken becomes monstrous, tap up to four target creatures. Those creatures don't untap during their controllers' untap steps for as long as you control Shipbreaker Kraken.

Flying, trample

Shroud (This creature can't be the target of spells or abilities.)

Flying

When Sky Swallower enters the battlefield, target opponent gains control of all other permanents you control.

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.

Trample

Phasing (This phases in or out before you untap during each of your untap steps. While it's phased out, it's treated as though it doesn't exist.)

At the beginning of your upkeep, all lands you control phase out. (They phase in before you untap during your next untap step.)

Indestructible

As long as your devotion to blue is less than five, Thassa isn't a creature. (Each {U} in the mana costs of permanents you control counts toward your devotion to blue.)

At the beginning of your upkeep, scry 1.

{1}{U}: Target creature you control can't be blocked this turn.

Whenever Thing from the Deep attacks, sacrifice it unless you sacrifice an Island.

Tidal Kraken can't be blocked.

At the beginning of your upkeep, mill seven cards.

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.)

When Wormfang Behemoth enters the battlefield, exile all cards from your hand.

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

Flying

When Wormfang Manta enters the battlefield, you skip your next turn.

When Wormfang Manta leaves the battlefield, you take an extra turn after this one.

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.