Ichthyomorphosis

Enchant creature
Enchanted creature loses all abilities and is a blue Fish with base power and toughness 0/1.

Eel Umbra

Flash (You may cast this spell any time you could cast an instant.)
Enchant creature
Enchanted creature gets +1/+1.
Umbra armor (If enchanted creature would be destroyed, instead remove all damage from it and destroy this Aura.)

Fortress Crab

Ghostform

Up to two target creatures can't be blocked this turn.

Purple-Crystal Crab

When Purple-Crystal Crab dies, draw a card.

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.)

Skitter Eel

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

Ice Cage

Enchant creature
Enchanted creature can't attack or block, and its activated abilities can't be activated.
When enchanted creature becomes the target of a spell or ability, destroy Ice Cage.

Jwari Scuttler

Chromeshell Crab

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.

Phantasmal Form

Until end of turn, up to two target creatures each have base power and toughness 3/3, gain flying, and become blue Illusions in addition to their other colors and types.
Draw a card.

Runner's Bane

Enchant creature with power 3 or less
When Runner's Bane enters, tap enchanted creature.
Enchanted creature doesn't untap during its controller's untap step.

Horseshoe Crab

Scuttlegator

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.

Island

Paralyzing Grasp

Enchant creature
Enchanted creature doesn't untap during its controller's untap step.

Ancient Crab

Stealth Mission

Put two +1/+1 counters on target creature you control. That creature can't be blocked this turn.

Wishcoin Crab

Slimebind

Flash (You may cast this spell any time you could cast an instant.)
Enchant creature
Enchanted creature gets -4/-0.

Claustrophobia

Enchant creature
When Claustrophobia enters, tap enchanted creature.
Enchanted creature doesn't untap during its controller's untap step.