Dendar the Night Serpent (CR 26)

Colossal Outsider (Evil and Extraplanar)
Alignment: Neutral evil
Initiative: +7; Senses: darkvision 120 ft., low-light vision, true seeing, Listen +65, and Spot +65

AC: 42 (-8 size, +6 Dex, +34 natural) touch 8, flat-footed 30
Hit Dice: 54d8+864 (1,193 hp); DR: 15/epic and good
Fort +45, Ref +35, Will +39
Speed: 80 ft., climb 80 ft.
Space: 50 ft./40 ft.
Base Attack +54; Grapple +89
Attack: bite +65 melee
Full Attack: bite +65 melee
Damage: bite 4d8+19/19-20 plus nightmare venom)
Special Attacks/Actions: Crush, ignore armor, improved grab, nightmare scales, nightmare venom, spell-like abilities, swallow whole, unleash nightmares
Abilities: Str 48, Dex 23, Con 42, Int 23, Wis 26, Cha 24
Special Qualities: fast healing 10, immunity to charm, death, and fear magic, immunity to petrification, immunity to poison, resistance to acid 10, cold 10, electricity 10, fire 10, and sonic 10, SR 40
Feats: Ability Focus (nightmare venom); Blind-fight; Cleave; Combat Reflexes; Great Cleave; Improved Critical (bite); Improved Bull Rush; Improved Initiative; Improved Natural Armor (6); Improved Overrun; Improved Sunder; Iron Will; Power Attack; Quicken Spell-Like Ability (shadow evocation)
Skills: Bluff +64, Climb +64, Concentration +73, Diplomacy +44, Hide +47, Jump +76, Knowledge (arcana) +63, Knowledge (the planes) +63, Listen +65, Move Silently +63, Search +63, Sense Motive +45, Spellcraft +43, Spot +65, Survival +31, and Swim +76
Advancement: -
Climate/Terrain: The Fugue Plane
Organization: Solitary
Treasure/Possessions: None

Source: Champions of Ruin

Crush (Ex): As a standard action, Dendar can jump, roll, or slither onto her opponents, using her whole body to crush them: She can crush creatures of Large size or smaller, up to as many as will fit under her gigantic body. Creatures crushed by the Night Serpent take 4d8+28 points of bludgeoning damage and must attempt a DC 45 Reflex save. Failure means the creature is pinned beneath her body, automatically taking crush damage each round the pin is maintained.

Ignore Armor (Ex): Dendar's incredibly sharp fangs pierce any armor as if it were paper. Not even the most powerful magic armor protects against her vicious bites; as a result, do not count armor and natural armor bonuses when determining an opponent's AC against the Night Serpent's bite attacks.

Improved Grab (Ex): To use this ability, Dendar must hit with her bite attack. She can then attempt to start a grapple as a free action without provoking attacks of opportunity.

Nightmare Scales (Su): Anyone striking the Night Serpent in melee combat causes one of her scales to fly off. Each scale contains a consumed nightmare, which is unleashed on the character in the form of a nightmare spell (DC 26).

Nightmare Venom (Ex): Anyone struck by Dendar's bite attack must succeed on a DC 53 Fortitude save or fall into a coma. While in this state, the character is assailed by a constant stream of his worst nightmares. The only way to recover a character in this state is through the use of a wish or miracle spell, and even then the character must succeed on a DC 53 Will save or take 1d4 points of Wisdom drain from the horrible lucid nightmares he has experienced.

Spell-Like Abilities: At will - dream, fear (DC 25), nightmare (DC 26), plane shift, shadow conjuration (DC 25), and shadow evocation (DC 26). Caster level 30th. The save DCs are Charisma-based and include a +4 racial bonus.

Swallow Whole (Ex): When Dendar begins her turn with a grappled opponent in her mouth, she can swallow that opponent with a successful grapple check. Once inside, a creature takes 2d10+28 points of bludgeoning damage per round from her muscular contractions. There are worse things inside the Night Serpent's gizzard, however.

The undigested nightmares of thousands of souls reside within Dendar's belly. Anyone trapped within is automatically assailed by these nightmares 1d6 times per round as if they had struck her in combat (the Will save is affected as if Dendar had one of the character's body parts).

There are two ways to escape this nightmare prison. The first is to deal at least 100 points of damage to the Night Serpent's gizzard with a light slashing or piercing weapon (her gizzard has an AC of 27). Once a creature has escaped in this way, muscular action closes the hole; other swallowed creatures must cut their own way out. The second method of escape is under Dendar's control. If she ever uses her unleash nightmares ability with a creature in her gizzard, the creature is automatically expelled along with the nightmares, suffering the nightmare attack along with all others in the area of effect (and possibly finding its way right back into her belly).

Dendar's interior can hold 2 Gargantuan, 4 Huge, 8 Large, 32 Medium, 128 Small, 512 Tiny, 2,048 Diminutive, or 8,192 Fine or smaller opponents.

True Seeing (Su): Dendar the Night Serpent continuously uses this ability, as the spell (caster level 30th).

Unleash Nightmares (Su): The Night Serpent can cause any being on any plane to relive her worst nightmare. Unless the creature succeeds at a DC 26 Will save, she goes completely insane. This insanity can be cured only by a limited wish, miracle, or wish spell. Dendar can unleash this ability us a breath weapon in combat once every 1d4 rounds as well, although she is loathe to do so since it delays the end of the world just that much longer. If she does so, all creatures within a 100-foot cone must make the saving throw, and those that fail are carried by their own nightmares into the Night Serpent's belly, in addition to being driven insane.

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.