Echinoloth (Yugoloth) (CR 8)

Large Outsider (Aquatic, Evil, and Extraplanar)
Alignment: Always neutral evil
Initiative: +5; Senses: tremorsense 60 ft., Listen +10, and Spot +10
Languages: Telepathy 100 ft.

AC: 17 (+1 Dex, +6 natural), touch 11, flat-footed 16
Hit Dice: 8d8+40 (76 hp); DR: 5/good
Fort +11, Ref +7, Will +5
Speed: 30 ft., climb 30 ft.
Space: 10 ft./10 ft. (5 ft. with bite)
Base Attack +8; Grapple +18
Attack: Tentacle +13 melee
Full Attack: 4 tentacles +13 melee and bite +8 melee
Damage: Tentacle 1d6+6, bite 1d8+3
Special Attacks/Actions: Infernal wound, nauseating aura, rend 2d6+9, summon yugoloth
Abilities: Str 22, Dex 13, Con 20, Int 6, Wis 8, Cha 11
Special Qualities: Amphibious, immunity to acid and poison, immunity to gaze attacks, illusions, visual effects, and other attack forms that rely on sight, resistance to cold 10, electricity 10, and fire 10, SR 20
Feats: Cleave; Improved Initiative; Power Attack
Skills: Climb +14, Escape Artist +12, Hide +8, Listen +10, Move Silently +12, Search +9, Spot +10, Survival -1 (+1 following tracks), and Use Rope +1 (+3 involving bindings)
Advancement: 9-16 HD (Large); 17-24 HD (Huge)
Climate/Terrain: Gray Waste of Hades
Organization: Solitary, cluster (3-5), or tangle (7-12)
Treasure/Possessions: Standard

Source: Stormwrack

An echinoloth's natural weapons, as well as any weapons it wields, are treated as evil-aligned for the purpose of overcoming damage reduction.

Infernal Wound (Su): The damage an echinoloth deals as it rends with its terrible hooked tentacles causes persistent wounds. Any creature injured by the echinoloth's rend attack loses 1 additional hit point each round. The wound does not heal naturally and resists healing spells. The continuing hit point loss can be stopped by a DC 19 Heal check, a cure spell, or a heal spell. However, a character attempting to cast a cure spell or a heal spell on a creature damaged by the echinoloth's tentacles must succeed on a DC 19 caster level check, or the spell has no effect on the injured character. The check DC is Constitution-based.

Nauseating Aura (Su): Target becomes nauseated for 1 round, range 30 feet, Fortitude DC 14 negates. The save DC is Charisma-based.

Rend (Ex): If an echinoloth hits a target with at least two tentacle attacks, it latches onto the opponent's body and tears the flesh. This attack automatically deals an extra 2d6+9 points of damage and subjects the target to its infernal wound ability.

Summon Yugoloth (Sp): Once per day, an echinoloth can attempt to summon one echinoloth with a 40% chance of success. This ability has a range of 30 feet and is the equivalent of a 5th-level spell. An echinoloth that is itself summoned cannot use its own summon ability for 1 hour.

Amphibious (Ex): Although echinoloths are aquatic, they can survive indefinitely on land.

Telepathy (Su): An echinoloth can communicate telepathically with any other creature within 100 feet that has a language.

Tremorsense (Ex): The hooks and tendrils on an echinoloth's body are highly sensitive to vibration, allowing it to pinpoint the location of anything within 60 feet that is in contact with the ground or surrounding water. Beyond that range, they treat all targets as having total concealment.

Skills: An echinoloth has a +8 racial bonus on Climb checks. It can always choose to take 10 on a Climb check, even if rushed or threatened.

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.

Evil Subtype

A subtype usually applied only to outsiders native to the evil-aligned Outer Planes. Evil outsiders are also called fiends. Most creatures that have this subtype also have evil alignments; however, if their alignments change, they still retain the subtype. Any effect that depends on alignment affects a creature with this subtype as if the creature has an evil alignment, no matter what its alignment actually is. The creature also suffers effects according to its actual alignment. A creature with the evil subtype overcomes damage reduction as if its natural weapons and any weapons it wields were evil-aligned (see Damage Reduction).

Extraplanar Subtype

A subtype applied to any creature when it is on a plane other than its native plane. A creature that travels the planes can gain or lose this subtype as it goes from plane to plane. This book assumes that encounters with creatures take place on the Material Plane, and every creature whose native plane is not the Material Plane has the extraplanar subtype (but would not have when on its home plane). An extraplanar creatures usually has a home plane mentioned in its description. These home planes are taken from the Great Wheel cosmology of the D&D game (see Chapter 5 of the Dungeon Master's Guide). If your campaign uses a different cosmology, you will need to assign different home planes to extraplanar creatures.

Creatures not labeled as extraplanar are natives of the Material Plane, and they gain the extraplanar subtype if they leave the Material Plane. No creature has the extraplanar subtype when it is on a transitive plane; the transitive planes in the D&D cosmology are the Astral Plane, the Ethereal Plane, and the Plane of Shadow.