Skittering Crustacean

{6}{U}: Monstrosity 4. (If this creature isn't monstrous, put four +1/+1 counters on it and it becomes monstrous.)
As long as this creature is monstrous, it has hexproof. (It can't be the target of spells or abilities your opponents control.)

Scrabbling Skullcrab

Eerie — Whenever an enchantment you control enters and whenever you fully unlock a Room, target player mills two cards. (They put the top two cards of their library into their graveyard.)

Sol Ring

Fathom Seer

Morph—Return two Islands you control to their owner's hand. (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)
When this creature is turned face up, draw two cards.

Ior Ruin Expedition

Landfall — Whenever a land you control enters, you may put a quest counter on this enchantment.
Remove three quest counters from this enchantment and sacrifice it: Draw two cards.

Canyon Crab

{1}{U}: This creature gets +2/-2 until end of turn.
At the beginning of your end step, if you haven't cast a spell from your hand this turn, draw a card, then discard a card.

Jwari Scuttler

Ruin Crab

Landfall — Whenever a land you control enters, each opponent mills three cards. (To mill a card, a player puts the top card of their library into their graveyard.)

Hedron Scrabbler

Landfall — Whenever a land you control enters, this creature gets +1/+1 until end of turn.

Tideforce Elemental

{U}, {T}: You may tap or untap another target creature.
Landfall — Whenever a land you control enters, you may untap this creature.

Island

Command Tower

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

Daze

You may return an Island you control to its owner's hand rather than pay this spell's mana cost.
Counter target spell unless its controller pays {1}.

Gilded Scuttler

This creature can't be blocked.
When this creature enters, tap target creature an opponent controls and put a stun counter on it. (If a permanent with a stun counter would become untapped, remove one from it instead.)

Iceberg Cancrix

Whenever another snow permanent you control enters, you may have target player mill two cards.

Hedron Crab

Landfall — Whenever a land you control enters, target player mills three cards. (They put the top three cards of their library into their graveyard.)

Ancient Crab

Flooded Shoreline

{U}{U}, Return two Islands you control to their owner's hand: Return target creature to its owner's hand.

Horseshoe Crab

Scuttletide

{1}, Discard a card: Create a 0/3 blue Crab creature token.
Delirium — Crabs you control get +1/+1 as long as there are four or more card types among cards in your graveyard.

Tidal Bore

You may return an Island you control to its owner's hand rather than pay this spell's mana cost.
You may tap or untap target creature.

High Tide

Until end of turn, whenever a player taps an Island for mana, that player adds an additional {U}.

Hard Evidence

Create a 0/3 blue Crab creature token.
Investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.")

Retreat to Coralhelm

Landfall — Whenever a land you control enters, choose one —
• You may tap or untap target creature.
• Scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Shorecomber Crab

Skyclave Squid

Defender
Landfall — Whenever a land you control enters, this creature can attack this turn as though it didn't have defender.

Arcane Signet

Staff of the Mind Magus

Whenever you cast a blue spell or an Island you control enters, you gain 1 life.

Purple-Crystal Crab

Coral Atoll

This land enters tapped.
When this land enters, sacrifice it unless you return an untapped Island you control to its owner's hand.
{T}: Add {C}{U}.