High Alert

Each creature you control assigns combat damage equal to its toughness rather than its power.
Creatures you control can attack as though they didn't have defender.
{2}{W}{U}: Untap target creature.

Fortress Crab

Island

Riptide Crab

Vigilance
When Riptide Crab dies, draw a card.

Unsummon

Return target creature to its owner's hand.

Vapor Snag

Return target creature to its owner's hand. Its controller loses 1 life.

Horseshoe Crab

Veteran Armorer

Ancient Crab

Purple-Crystal Crab

When Purple-Crystal Crab dies, draw a card.