Giant CrabCreature 2
Source Pathfinder Monster Core 2
Perception +8 (darkvision)
Languages none
Skills Acrobatics +7, Athletics +8, Stealth +7
Str +4, Dex +3, Con +1, Int -4, Wis +2, Cha -3
AC 18; Fort +7; Reflex +9; Will +8;
HP 25
Speed 25 feet (swim 15 feet)
Resistances Physical 3
Claw
+9 (+4, -1) to hit (unarmed) 1d10+4 SlashingScuttle

Trigger A creature that the giant crab can see targets the crab with an attack
Effect The giant crab scuttles to the side and gains a +2 circumstance bonus to AC against the triggering attack. After the attack resolves, the crab can Stride up to its speed in a straight line as part of the reaction.
Vulnerable to ProneIf a creature critically succeeds on a check to Trip the giant crab, the crab is flipped over onto its back in addition to the usual effects. A giant crab that is flipped onto its back has a particularly hard time defending itself; instead of taking the normal -2 circumstance penalty to AC for being Off-Guard, it takes a -4 circumstance penalty to AC.
Constrict
(1d6+3) bludgeoning damage, DC 18 fortitude
The monster deals the listed amount of damage to any number of creatures Grabbed or Restrained by it. Each of those creatures can attempt a basic Fortitude save with the listed DC.
Grab
Requirements The monster's last action was a successful Strike that lists Grab in its damage entry, or the monster has a creature Grabbed or Restrained
Effect If used after a Strike, the monster attempts to [/act grapple] the creature using the body part it attacked with. This attempt neither applies nor counts toward the creature's multiple attack penalty.
The monster can instead use Grab and choose one creature it's grabbing or restraining with an appendage that has Grab to automatically extend that condition to the end of the monster's next turn.
Crabs are scavenging crustaceans known for their hard shells and iconic sideways gait. They use their claws to defend themselves, hunt, and fight other crabs for territory. When confronted with threats from outside their species, most crabs prefer to flee, but when retreat isn't possible, they clamp on to their foes as tightly as they can.
The statistics presented here represent giant crabs that live close to the water's surface. Crabs that live deeper underwater often exhibit more extreme adaptations to their environment. Crabs who live in the depths where little light reaches gain darkvision and cold resistance, and those adapted to the most hostile reaches of the deep sea can detect nearby creatures through subtle shifts in ocean currents.
These skittering creatures are prized for their delicious meat, but their size makes them dangerous targets for harvesting.
Traits
Anything that doesn't list another rarity trait (uncommon, rare, or unique) automatically has the common trait. This rarity indicates that an ability, item, or spell is available to all players who meet the prerequisites for it. A creature of this rarity is generally known and can be summoned with the appropriate summon spell.
AnimalAn animal is a creature with a relatively low intelligence. It typically doesn't have an Intelligence attribute modifier over –4, can't speak languages, and can't be trained in Intelligence-based skills.
AquaticAquatic creatures are at home underwater. Their bludgeoning and slashing unarmed Strikes don't take the usual –2 penalty for being underwater. Aquatic creatures can breathe water but not air.