Crayfish, Giant
Medium Animal
Hit Dice: 3d8+9 (21hp)
Initiative: +0
Speed: 30 ft., swim 30 ft.
AC: 15 (+5 natural)
Attacks: 2 claws +6 melee
Damage: Claws 1d6+4
Face/Reach: 5 ft. by 5 ft. / 5 ft.
Special Attacks: Improved Grab
Special Qualities: Amphibious
Saves: Fort +6, Ref +3, Will +1
Abilities: Str 18, Dex 10, Con 16, Int 2, Wis 11, Cha 10
Skills: Swim +14
Feats: None
Climate/Terrain: Seacoast or Underwater Cavern
Organization: Solitary, Troupe (2-8)
Challenge Rating: 2
Treasure: None
Alignment: Neutral
Advancement: 4-6 HD (Medium); 7-12 HD (Large)

Giant Crayfish are much like the smaller freshwater crustaceans of rivers and lakes and subterranean pools, only larger, anywhere from the size of dogs to the size of large horses. They have exoskeletons ranging from red to pink in some species or pale blue and white in subterranean examples. Their forelimbs end in massive claws, used for grasping prey.  They also have eight thinner legs used to support the body and tail. These do not aid in swimming, which is mainly accomplished by the wide tail. Subterranean Crayfish have no eyes, but instead possess blindsight to a 60’ range. Saltwater Crayfish are called lobster and do not differ in appearance. Lobster are not amphibious. 

Combat
     Improved Grab (Ex):  If on any round both claws hit a size medium or small creature, the crab achieves a grapple automatically. If the creature attacked is size Tiny or Diminutive only one claw is necessary. Size Fine, Large or larger creatures remain unaffected by the grapple. Each round the victim is damaged 1d6+4 for each claw attached. The Crayfish may carry up to 400 pounds in two claws or 200 in one claw. A single claw is dislodged by a successful opposed grapple check.
     Amphibious (Ex):  A giant crayfish can survive on land for up to two hours before it begins to suffer subdual damage at a rate of 1d8 per hour. It suffers no penalties to combat while partially or completely submerged in water.