Spells your opponents cast that target Charix, the Raging Isle cost {2} more to cast. {3}: Charix gets +X/-X until end of turn, where X is the number of Islands you control.

Morph {4}{U} (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 Chromeshell Crab is turned face up, you may exchange control of target creature you control and target creature an opponent controls.

Flash

Ward {2} (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {2}.) {3}{U}{U}: Dreadlight Monstrosity can't be blocked this turn. Activate only if you own a card in exile.

{U}: Giant Crab gains shroud until end of turn. (It can't be the target of spells or abilities.)

{2}{G}: Adapt 2. (If this creature has no +1/+1 counters on it, put two +1/+1 counters on it.) Whenever one or more +1/+1 counters are put on Growth-Chamber Guardian, you may search your library for a card named Growth-Chamber Guardian, reveal it, put it into your hand, then shuffle.

Landfall — Whenever a land enters the battlefield under your control, target player mills three cards.

{U}: Untap Horseshoe Crab.

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

{1}{U}, {T}: Put target green creature on top of its owner's library.

Ward {3} (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {3}.) Channel — {2}{U}, Discard Mirrorshell Crab: Counter target spell or ability unless its controller pays {3}.

When Purple-Crystal Crab dies, draw a card.

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

Whenever Salvage Scuttler attacks, return an artifact you control to its owner's hand.

Defender {6}{G/U}{G/U}: Adapt 3. (If this creature has no +1/+1 counters on it, put three +1/+1 counters on it.) As long as Scuttlegator has a +1/+1 counter on it, it can attack as though it didn't have defender.

Flash (You may cast this spell any time you could cast an instant.) Evolve (Whenever a creature enters the battlefield under your control, if that creature has greater power or toughness than this creature, put a +1/+1 counter on this creature.)

{2}{G}{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 Sharktocrab, tap target creature an opponent controls. That creature doesn't untap during its controller's next untap step.

{2}{U}: Adapt 2. (If this creature has no +1/+1 counters on it, put two +1/+1 counters on it.)

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

Bestow {5}{U} (If you cast this card for its bestow cost, it's an Aura spell with enchant creature. It becomes a creature again if it's not attached to a creature.) Whenever Thassa's Emissary or enchanted creature deals combat damage to a player, draw a card. Enchanted creature gets +3/+3.