This creature can't be blocked.

This creature can't be blocked. Whenever another Merfolk you control enters, this creature gets +1/+1 until end of turn.

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.

As this artifact enters, choose a creature type. Whenever you cast a spell of the chosen type, put a charge counter on this artifact. Creatures you control of the chosen type get +1/+1 for each charge counter on this artifact.

Other Merfolk get +1/+1 and have islandwalk. (They can't be blocked as long as defending player controls an Island.)

Other Merfolk creatures you control get +1/+1 and have islandwalk. (They can't be blocked as long as defending player controls an Island.)

Other Merfolk you control get +1/+1.

Other Merfolk creatures you control get +1/+1. {T}: Target Merfolk creature can't be blocked this turn.

Until end of turn, creatures you control get +1/+1 and gain trample and infect. (Creatures with infect deal damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)

Counter target spell. Its controller may draw up to two cards at the beginning of the next turn's upkeep. You draw a card at the beginning of the next turn's upkeep.

Destroy target permanent. Its controller creates a 3/3 green Beast creature token.

Return target nonland permanent you don't control to its owner's hand. Overload {6}{U} (You may cast this spell for its overload cost. If you do, change "target" in its text to "each.")

Counter target spell, activated ability, or triggered ability. (Mana abilities can't be targeted.)

Split second (As long as this spell is on the stack, players can't cast spells or activate abilities that aren't mana abilities.) Destroy target artifact or enchantment.

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.

Flash When this creature enters, tap target creature an opponent controls. It loses all abilities until end of turn.

Destroy target creature. It can't be regenerated. That creature's controller creates a 3/3 green Frog Lizard creature token.

Whenever another Merfolk you control enters, put a +1/+1 counter on target Merfolk you control.

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

{T}, Sacrifice this land: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

{T}: Add {C}. {G/U}, {T}: Add {G}{G}, {G}{U}, or {U}{U}.

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

This land enters tapped unless you control a Forest or an Island. {T}: Add {G} or {U}.

This land enters tapped. {T}: Add {G} or {U}. {2}{G}{U}: This land becomes a 3/3 green and blue Elemental creature with hexproof until end of turn. It's still a land.

{T}: Add {C}. {G}{U}, {T}: Put a +1/+1 counter on each creature that entered this turn.

This land enters tapped. {T}: Add one mana of any color in your commander's color identity. When that mana is spent to cast a creature spell that shares a creature type with your commander, scry 1. (Look at the top card of your library. You may put that card on the bottom.)

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

{T}: Add {C}. {4}, {T}: Target creature can't be blocked this turn.

This land enters tapped. When this land enters, return a land you control to its owner's hand. {T}: Add {G}{U}.

({T}: Add {G}.)

({T}: Add {U}.)

This land enters tapped. When this land enters, scry 1. (Look at the top card of your library. You may put that card on the bottom.) {T}: Add {G} or {U}.

{T}: Add {C}{C}. Activate only if you control five or more lands.

{T}, Sacrifice this land: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

As this land enters, choose a creature type. {T}: Add {C}. {T}: Add one mana of any color. Spend this mana only to cast a creature spell of the chosen type.

As this creature enters, choose a creature type. This creature is the chosen type in addition to its other types. Other creatures you control of the chosen type get +1/+1.

Permanents you control gain hexproof and indestructible until end of turn.

Spells your opponents cast that target a Merfolk you control cost {2} more to cast. Abilities your opponents activate that target a Merfolk you control cost {2} more to activate.

Whenever you cast a Merfolk spell, create a 1/1 blue Merfolk creature token with hexproof. (A creature with hexproof can't be the target of spells or abilities your opponents control.)

{1}{U}: Adapt 1. (If this creature has no +1/+1 counters on it, put a +1/+1 counter on it.) Whenever one or more +1/+1 counters are put on this creature, draw a card, then discard a card.

Whenever a creature you control deals combat damage to a player, you may draw a card. {1}{U}, {T}: Creatures your opponents control attack this turn if able.

Islandwalk (This creature can't be blocked as long as defending player controls an Island.) Whenever this creature deals combat damage to a player, you may draw that many cards.

Choose a creature type. Draw a card for each permanent you control of that type.

Whenever this creature becomes tapped, you may draw a card.

Whenever a nontoken creature you control enters, if it doesn't have the same name as another creature you control or a creature card in your graveyard, draw a card.

When this creature enters, it explores, then it explores again. (Reveal the top card of your library. Put that card into your hand if it's a land. Otherwise, put a +1/+1 counter on this creature, then put the card back or put it into your graveyard. Then repeat this process.)

As this enchantment enters, choose a creature type. Whenever a creature you control of the chosen type enters or attacks, draw a card.

At the beginning of your upkeep, scry 1. Whenever you cast a creature spell, you may pay {G}. If you do, draw a card.

When this creature enters, it explores. (Reveal the top card of your library. Put that card into your hand if it's a land. Otherwise, put a +1/+1 counter on this creature, then put the card back or put it into your graveyard.)

Whenever a Merfolk you control deals combat damage to a player, draw a card.

As an additional cost to cast this spell, reveal a Merfolk card from your hand or pay {3}. When this creature enters, draw a card.

As this artifact enters, choose a creature type. Creatures you control of the chosen type get +1/+1. Whenever you cast a creature spell of the chosen type, draw a card.

When this creature enters, draw a card.

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

Creatures you control have "{T}: Add one mana of any color."

Search your library for up to two basic land cards, reveal those cards, put one onto the battlefield tapped and the other into your hand, then shuffle.

Draw a card. You may put a land card from your hand onto the battlefield.

As this artifact enters, choose a creature type. Creature spells you cast of the chosen type cost {1} less to cast. At the beginning of your upkeep, look at the top card of your library. If it's a creature card of the chosen type, you may reveal it and put it into your hand.

Search your library for up to two basic land cards, reveal those cards, put one onto the battlefield tapped and the other into your hand, then shuffle.

Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Untap all permanents you control during each other player's untap step.

{1}, {T}: Add {G}{U}.

{T}: Add {C}{C}.

When this creature enters, you may search your library for a Merfolk card, reveal it, then shuffle and put that card on top. Whenever another Merfolk you control enters, put a +1/+1 counter on this creature.

Islandwalk (This creature can't be blocked as long as defending player controls an Island.) When this creature enters, you may search your library for a Merfolk card, reveal it, then shuffle and put that card on top.