This lumbering hard-shelled crab stands as tall as a dwarf, its massive pincers waving menacingly.
As a summoned, template, creature, this creature has several changes. Anything noted with  is what it gains from the template associated with the summoners’ alignment. Divine is always listed first, and Unholy afterwards.
Giant Crab (CR 2)
AC 16, touch 11, flat-footed 15 (+1 Dex, +5 natural)
hp 19  (3d8+6)
Fort +5, Ref +2, Will +1
Immune Mind-affecting effects;
Resist Water 5 [holy 5/shadow 5]
Weakness Ice [shadow/holy]
Speed 30 ft. [40 ft], Swim 20 ft. [30 ft]
Melee 2 Claws +4 (1d4+2 [+1d4 holy/shadow] plus grab)
Space 5 ft.; Reach 5 ft.
Special Attack Constrict (1d4+2)
Str 15, Dex 13, Con 14, Int —, Wis 10, Cha 2
Base Atk +2; CMB +4 (+8 grapple); CMD 15 (27 vs. trip)
Skills Perception +4, Swim +10; Racial Modifiers +4 Perception
SQ water dependency
Giant Crab can use both claws as a standard action every 1d4 rounds while doing 1d6+3 bludgeoning damage per claw.
Water Dependency (Ex)
Crabs can survive out of the water for 1 hour per point of Constitution. Beyond this limit, a crab runs the risk of suffocation, as if it were drowning.