Scyllan (CR 13)

Huge Outsider (Aquatic and Native)
Alignment: Always lawful evil
Initiative: +7 (+3 Dex, +4 Improved Initiative); Senses: darkvision 60 ft., Listen +24, and Spot +24

AC: 29 (-2 size, +3 Dex, +18 natural), touch 11, flat-footed 26
Hit Dice: 16d8+112 (184 hp); DR: 10/magic and silver
Fort +17, Ref +13, Will +15
Speed: Swim 50 ft.
Space: 15 ft./15 ft. (30 ft. with tentacle)
Base Attack +16; Grapple +35
Attack: Tentacle +25 melee
Full Attack: 4 tentacles +25 melee and 2 claws +23 melee
Damage: Tentacle 1d8+11, Claw 2d6+5
Special Attacks/Actions: Constrict 1d8+11, control water, frightful noise, improved grab, swallow whole
Abilities: Str 33, Dex 17, Con 25, Int 8, Wis 20, Cha 6
Special Qualities: SR 27
Feats: Ability Focus (frightful noise); Improved Initiative; Improved Natural Attack (claw); Multiattack; Swim-By Attack; Weapon Focus (tentacle)
Skills: Hide +14, Intimidate +17, Jump +38, Knowledge (nature) +20, Listen +24, Spot +24, Survival +26, and Swim +19
Advancement: 17-24 HD (Huge); 25-32 HD (Gargantuan)
Climate/Terrain: Cold aquatic
Organization: Solitary
Treasure/Possessions: Double standard

Source: Stormwrack

Constrict (Ex): A scyllan deals 1d8+11 points of damage with a successful grapple check made with a claw.

Control Water (Sp): 1/hour, caster level 16th.

Frightful Noise (Su): A scyllan produces a wailing sound by blowing air through the comblike growths on its head. This horrible racket is unsettling to nearby creatures. The scyllan activates its frightful noise as a move action and can end it anytime as a free action. Creatures within 100 feet of the scyllan are subject to the effect if they have fewer HD than the scyllan.

A potentially affected creature who succeeds on a DC 18 Will save is immune to that scyllan's frightful noise for 24 hours. On a failure, creatures with 4 or fewer HD become panicked for 2d6 rounds and those with 5 or more HD become shaken for 2d6 rounds. Scyllans are unaffected by the frightful noise of other scyllans. Frightful noise is a sonic, mind-affecting compulsion. The save DC is Charisma-based and includes a +2 bonus from the Ability Focus feat.

Improved Grab (Ex): To use this ability, a scyllan must hit with a tentacle attack. It can then attempt to start a grapple as a free action without provoking attacks of opportunity. If it wins the grapple check, it establishes a hold and can transfer the grabbed creature to a claw as a free action or attempt to swallow it whole. A scyllan that transfers a creature to its claw can constrict.

Swallow Whole (Ex): A scyllan can try to swallow a grabbed opponent by making a successful grapple check. Once inside, the opponent takes 2d8+16 points of crushing damage plus 2d6 points of acid damage per round. A swallowed creature can cut its way out using a light slashing or piercing weapon to deal 25 points of damage to the maw (AC 17). Once the creature exits, muscular action closes the hole; another swallowed opponent must cut its own way out.

A Huge scyllan's maw holds 2 Large, 8 Medium, 32 Small, 128 Tiny, or 512 Diminutive or smaller opponents.

Skills: A scyllan has a +8 racial bonus on any Swim check to perform some special action or avoid a hazard. It can always choose to take 10 on a Swim check, even if distracted or endangered. It can use the run action while swimming, provided it swims in a straight line.

Aquatic Subtype

Creatures with the aquatic subtype always have swim speeds and thus can move in water without making Swim checks. An aquatic creature can breathe underwater. It cannot also breathe air unless it has the amphibious special quality.

Native Subtype

A subtype applied only to outsiders. These creatures have mortal ancestors or a strong connection to the Material Plane and can be raised, reincarnated, or resurrected just as other living creatures can be. Creatures with this subtype are native to the Material Plane (hence the subtype's name).

Unlike true outsiders, native outsiders need to eat and sleep.