This creature has a cat-like body with eight tentacles instead of legs. Its head is clearly feline, though more elongated and streamlined. It also has beak instead of jaws, and thick tendrils instead of whiskers.
CR 3; XP 800
N Small Aberration (aquatic)
Init +8; Senses darkvision 60 ft., keen scent, low-light vision, scent; Perception +14
AC 16, touch 15, flat-footed 12 (+4 Dex, +1 natural, +1 size)
hp 26 (4d8+8)
Fort +3, Ref +5, Will +6
Defensive Abilities aquatic evasion
Speed 20 ft., climb 20 ft., swim 50 ft.
Melee bite +8 (1d4+1), tentacles +3 touch (attach, paralytic grasp)
Space 5 ft.; Reach 5 ft.
Special Attacks pounce, sneak attack +2d6
Str 12, Dex 18, Con 14, Int 2, Wis 15, Cha 11
Base Atk +3; CMB +3; CMD 17 (29 vs trip)
Feats Improved Initiative, Weapon Finesse
Skills Acrobatics +8, Climb +13, Perception +14, Stealth +16, Swim +13; Racial Modifiers +8 Perception, +8 Stealth
SQ amphibious, compression
Environment tropical oceans
Organization solitary or pair
Aquatic Evasion (Ex) A tentaculcat benefits from evasion special ability while swimming.
Paralytic Grasp (Ex) The touch of a tentaculcat long feeding tentacles can short circuit nerves and cause paralysis on a failed Fortitude saving throw (DC 14). A creature affected by paralytic grasp can keep repeating its saving throw each round. A creature that succeeds the saving throw becomes immune to tentaculcats' paralytic grasp for 24 hours. A tentaculcat can suppress this ability, usually when it is using its tentacles to feel an object or creature peacefully or playfully. The saving throw DC is Constitution-based. This is a pain effect.
Tentaculcats live in shallow tropical seas and oceans and on their shores where they hunt and feed on crustaceans, fishes, and other small critters, as well as tropical fruits. They are curious and playful creatures, rarely harming humanoids, though they can lash quickly against perceived threat.
A 7th level spellcaster with Improved Familiar feat can select tentaculcat as a familiar and characters with Leadership can pick it as a 5th level cohort (advancing by taking rogue levels). It often involves being subject to its paralytic grasp when it wants to show its displeasure, though.