Put a flood counter on target land. That land is an Island in addition to its other types for as long as it has a flood counter on it. If you control a Merfolk, draw a card.
{6}
Caged Sun
Artifact
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.
{U}
Caller of Gales
Creature - Merfolk Wizard
{1}{U}, {T}: Target creature gains flying until end of turn.
1 /
1
{3}{U}
Clone
Creature - Shapeshifter
You may have Clone enter the battlefield as a copy of any creature on the battlefield.
0 /
0
{3}{U}
Clone
Creature - Shapeshifter
You may have Clone enter the battlefield as a copy of any creature on the battlefield.
0 /
0
{1}{U}
Convincing Mirage
Enchantment - Aura
Enchant land
As Convincing Mirage enters the battlefield, choose a basic land type.
Enchanted land is the chosen type.
{U}
Cosi's Trickster
Creature - Merfolk Wizard
Whenever an opponent shuffles their library, you may put a +1/+1 counter on Cosi's Trickster.
1 /
1
{U}{U}
Counterspell
Instant
Counter target spell.
{U}{U}
Counterspell
Instant
Counter target spell.
{U}{U}
Counterspell
Instant
Counter target spell.
{U}{U}
Counterspell
Instant
Counter target spell.
{U}
Enclave Cryptologist
Creature - Merfolk Wizard
Level up {1}{U} ({1}{U}: Put a level counter on this. Level up only as a sorcery.)
LEVEL 1-2
0/1
{T}: Draw a card, then discard a card.
LEVEL 3+
0/1
{T}: Draw a card.
0 /
1
{1}{U}
Halimar Wavewatch
Creature - Merfolk Soldier
Level up {2} ({2}: Put a level counter on this. Level up only as a sorcery.)
LEVEL 1-4
0/6
LEVEL 5+
6/6
Islandwalk (This creature can't be blocked as long as defending player controls an Island.)
0 /
3
--
Island
Basic Land - Island
({T}: Add {U}.)
--
Island
Basic Land - Island
({T}: Add {U}.)
--
Island
Basic Land - Island
({T}: Add {U}.)
--
Island
Basic Land - Island
({T}: Add {U}.)
--
Island
Basic Land - Island
({T}: Add {U}.)
--
Island
Basic Land - Island
({T}: Add {U}.)
--
Island
Basic Land - Island
({T}: Add {U}.)
--
Island
Basic Land - Island
({T}: Add {U}.)
--
Island
Basic Land - Island
({T}: Add {U}.)
--
Island
Basic Land - Island
({T}: Add {U}.)
--
Island
Basic Land - Island
({T}: Add {U}.)
--
Island
Basic Land - Island
({T}: Add {U}.)
--
Island
Basic Land - Island
({T}: Add {U}.)
--
Island
Basic Land - Island
({T}: Add {U}.)
--
Island
Basic Land - Island
({T}: Add {U}.)
--
Island
Basic Land - Island
({T}: Add {U}.)
--
Island
Basic Land - Island
({T}: Add {U}.)
--
Island
Basic Land - Island
({T}: Add {U}.)
--
Island
Basic Land - Island
({T}: Add {U}.)
--
Island
Basic Land - Island
({T}: Add {U}.)
--
Island
Basic Land - Island
({T}: Add {U}.)
--
Island
Basic Land - Island
({T}: Add {U}.)
{2}{U}{U}
Levitation
Enchantment
Creatures you control have flying.
{U}{U}
Lord of Atlantis
Creature - Merfolk
Other Merfolk get +1/+1 and have islandwalk. (They can't be blocked as long as defending player controls an Island.)
2 /
2
{U}{U}
Lord of Atlantis
Creature - Merfolk
Other Merfolk get +1/+1 and have islandwalk. (They can't be blocked as long as defending player controls an Island.)
2 /
2
{U}{U}
Lord of Atlantis
Creature - Merfolk
Other Merfolk get +1/+1 and have islandwalk. (They can't be blocked as long as defending player controls an Island.)
2 /
2
{U}{U}
Lord of Atlantis
Creature - Merfolk
Other Merfolk get +1/+1 and have islandwalk. (They can't be blocked as long as defending player controls an Island.)
2 /
2
{1}{U}{U}
Lullmage Mentor
Creature - Merfolk Wizard
Whenever a spell or ability you control counters a spell, you may create a 1/1 blue Merfolk creature token.
Tap seven untapped Merfolk you control: Counter target spell.
2 /
2
{1}{U}{U}
Lullmage Mentor
Creature - Merfolk Wizard
Whenever a spell or ability you control counters a spell, you may create a 1/1 blue Merfolk creature token.
Tap seven untapped Merfolk you control: Counter target spell.
2 /
2
{1}{U}{U}
Lullmage Mentor
Creature - Merfolk Wizard
Whenever a spell or ability you control counters a spell, you may create a 1/1 blue Merfolk creature token.
Tap seven untapped Merfolk you control: Counter target spell.
2 /
2
{U}
Magical Hack
Instant
Change the text of target spell or permanent by replacing all instances of one basic land type with another. (For example, you may change "swampwalk" to "plainswalk." This effect lasts indefinitely.)
{1}{U}
Maritime Guard
Creature - Merfolk Soldier
1 /
3
{U}{U}
Master of the Pearl Trident
Creature - Merfolk
Other Merfolk creatures you control get +1/+1 and have islandwalk. (They can't be blocked as long as defending player controls an Island.)
2 /
2
{U}{U}
Master of the Pearl Trident
Creature - Merfolk
Other Merfolk creatures you control get +1/+1 and have islandwalk. (They can't be blocked as long as defending player controls an Island.)
2 /
2
{1}{U}
Merchant Scroll
Sorcery
Search your library for a blue instant card, reveal that card, put it into your hand, then shuffle.
{1}{U}{U}
Merfolk Sovereign
Creature - Merfolk Noble
Other Merfolk creatures you control get +1/+1.
{T}: Target Merfolk creature can't be blocked this turn.
2 /
2
{1}{U}{U}
Merfolk Sovereign
Creature - Merfolk Noble
Other Merfolk creatures you control get +1/+1.
{T}: Target Merfolk creature can't be blocked this turn.
2 /
2
{1}{U}{U}
Merfolk Sovereign
Creature - Merfolk Noble
Other Merfolk creatures you control get +1/+1.
{T}: Target Merfolk creature can't be blocked this turn.
2 /
2
{2}{U}
Merrow Reejerey
Creature - Merfolk Soldier
Other Merfolk creatures you control get +1/+1.
Whenever you cast a Merfolk spell, you may tap or untap target permanent.
2 /
2
{U}{U}
Muddle the Mixture
Instant
Counter target instant or sorcery spell.
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.)
{U}{U}
Muddle the Mixture
Instant
Counter target instant or sorcery spell.
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.)
{U}{U}
Muddle the Mixture
Instant
Counter target instant or sorcery spell.
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.)
{U}
Sandbar Merfolk
Creature - Merfolk
Cycling {2} ({2}, Discard this card: Draw a card.)
1 /
1
{U}
Skywatcher Adept
Creature - Merfolk Wizard
Level up {3} ({3}: Put a level counter on this. Level up only as a sorcery.)
LEVEL 1-2
2/2
Flying
LEVEL 3+
4/2
Flying
1 /
1
{U}
Skywatcher Adept
Creature - Merfolk Wizard
Level up {3} ({3}: Put a level counter on this. Level up only as a sorcery.)
LEVEL 1-2
2/2
Flying
LEVEL 3+
4/2
Flying
1 /
1
{U}
Skywatcher Adept
Creature - Merfolk Wizard
Level up {3} ({3}: Put a level counter on this. Level up only as a sorcery.)
LEVEL 1-2
2/2
Flying
LEVEL 3+
4/2
Flying
1 /
1
{U}
Skywatcher Adept
Creature - Merfolk Wizard
Level up {3} ({3}: Put a level counter on this. Level up only as a sorcery.)
LEVEL 1-2
2/2
Flying
LEVEL 3+
4/2
Flying
1 /
1
{1}{U}
Spreading Seas
Enchantment - Aura
Enchant land
When Spreading Seas enters, draw a card.
Enchanted land is an Island.
{1}{U}
Spreading Seas
Enchantment - Aura
Enchant land
When Spreading Seas enters, draw a card.
Enchanted land is an Island.
{1}{U}
Spreading Seas
Enchantment - Aura
Enchant land
When Spreading Seas enters, draw a card.
Enchanted land is an Island.
{3}{U}{U}
Vesuvan Doppelganger
Creature - Shapeshifter
You may have Vesuvan Doppelganger enter the battlefield as a copy of any creature on the battlefield, except it doesn't copy that creature's color and it has "At the beginning of your upkeep, you may have this creature become a copy of target creature, except it doesn't copy that creature's color and it has this ability."