Tenacious Hunter

As long as a creature has a -1/-1 counter on it, this creature has vigilance and deathtouch.

Sewer Crocodile

{3}{U}: This creature can't be blocked this turn. This ability costs {3} less to activate if there are five or more mana values among cards in your graveyard.

Spined Karok

Scaled Behemoth

Hexproof (This creature can't be the target of spells or abilities your opponents control.)

Algae Gharial

Shroud (This creature can't be the target of spells or abilities.)
Whenever another creature dies, you may put a +1/+1 counter on this creature.

Lurking Crocodile

Bloodthirst 1 (If an opponent was dealt damage this turn, this creature enters with a +1/+1 counter on it.)
Islandwalk (This creature can't be blocked as long as defending player controls an Island.)

The Pride of Hull Clade

This spell costs {X} less to cast, where X is the total toughness of creatures you control.
Defender
{2}{U}{U}: Until end of turn, target creature you control gets +1/+0, gains "Whenever this creature deals combat damage to a player, draw cards equal to its toughness," and can attack as though it didn't have defender.

Emperor Crocodile

When you control no other creatures, sacrifice this creature.

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 this creature has a +1/+1 counter on it, it can attack as though it didn't have defender.

Crocanura

Reach (This creature can block creatures with flying.)
Evolve (Whenever a creature you control enters, if that creature has greater power or toughness than this creature, put a +1/+1 counter on this creature.)

Crocodile of the Crossing

Haste
When this creature enters, put a -1/-1 counter on target creature you control.