Elder Brain (CR 25)

Large Aberration
Alignment: Always lawful evil
Initiative: +5 (+1 Dex, +4 Improved Initiative); Senses: blindsight 240 ft., telepathic awareness, Listen +38, and Spot +36
Languages: telepathy 350 ft.

AC: 30 (-1 size, +1 Dex, +20 natural), touch 10, flat-footed 29
Hit Dice: 26d8+364 plus 3 (484 hp); DR: 15/adamantine
Fort +24, Ref +11, Will +24
Speed: 10 ft., fly 30 ft. (good), swim 30 ft. (Elder brains use their base speed only when they are relocating themselves to a new pool.)
Space: 10 ft./10 ft.
Base Attack +19; Grapple +24
Attack: Tendril +20 melee
Full Attack: 4 tendrils +20 melee
Damage: Tendril 1d6+1 plus extract
Special Attacks/Actions: Extract, improved grab, mind blast, psionics, spells
Abilities: Str 13, Dex 13, Con 38, Int 28, Wis 25, Cha 26
Special Qualities: bud brain golem, regeneration 10, resistance to cold 10 and fire 10, SR 34
Feats: Alertness; Great Fortitude; Improved Initiative; Iron Will; Lightning Reflexes; Quicken Spel-Like Ability (charm monster); Quicken Spell-Like Ability (mass suggestion); Toughness; Weapon Focus (tendril)
Skills: Bluff +37, Concentration +43, Diplomacy +41, Disguise +8 (+10 acting in character), Intimidate +41, Knowledge (arcana) +38, Knowledge (history) +38, Knowledge (the planes) +38, Listen +38, Sense Motive +36, Spellcraft +42, Spot +36, and Survival +7 (+9 on other planes)
Advancement: 27-38 HD (Large); 39-78 HD (Huge)
Climate/Terrain: Underground
Organization: Solitary
Treasure/Possessions: Standard

Source: Lords of Madness

Extract (Ex): An elder brain that begins its turn with a tendril attached to an opponent and makes a successful grapple check automatically extracts the opponent's brain, instantly killing that creature. This power is useless against constructs, elementals, oozes, plants, and undead. Extraction is not instantly fatal to foes with multiple heads.

Improved Grab (Ex): To use this ability, an elder brain must hit a Small to Gargantuan creature with its tendril attack. If it gets a hold, it sinks the tendril into the opponent's head and can try to extract in the next round. The opponent can escape with a single successful grapple check or Escape Artist check, but the elder brain gets a +2 circumstance bonus for the deep attachment, and the opponent takes 1d6 points of damage from ripping the tendril free.

Mind Blast (Sp): This psionic attack is a cone 60 feet long. Anyone caught in this cone must succeed on a DC 31 Will save or be stunned for 3d4 rounds. An elder brain can use this ability once every 1d4 rounds. The save DC is Charisma-based. This ability is the equivalent of a 4th-level spell.

Psionics (Sp): At will - astral projection, charm monster (DC 22), detect thoughts (DC 20), dominate monster (DC 27), mass suggestion (DC 24), plane shift. Caster or manifester level 20th. The save DCs are Charisma-based.

Spells: An elder brain casts spells as a 20th-level sorcerer.

Typical Sorcerer Spells Known (6/8/8/8/8/7/7/7/7/6 per day; caster level 20th): 0 - acid splash (+19 ranged touch), daze (DC 18), detect magic, detect poison, flare (DC 18), mage hand, ray of frost (+19 ranged touch), read magic, touch of fatigue (+19 melee touch; DC 18) 1st - comprehend languages, identify, ray of enfeeblement (+19 ranged touch), shield, true strike; 2nd - locate object, obscure object (DC 20), resist energy, scorching ray (+19 ranged touch), touch of idiocy (+19 melee touch); 3rd - clairaudience/clairvoyance, dispel magic, displacement, nondetection; 4th - detect scrying, dimensional anchor (+19 ranged touch), Evards black tentacles, scrying (DC 22); 5th - dismissal (DC 23), sending, telekinesis (DC 23), teleport; 6th - analyze dweomer, chain lightning (DC 24), greater dispel magic; 7th - insanity (DC 25), summon monster VII, vision; 8th - discern location, maze, screen (DC 26); 9th - energy drain (+19 ranged touch), Mordenkainen's disjunction, prismatic sphere (DC 27).

Blindsight (Ex): An elder brain has no visual organs but can "see" by using psychic energy to ascertain objects and creatures within 240 feet.

Bud Brain Golem (Ex): Once per day, an elder brain can bud a portion of its flesh, forming a golemlike creature composed of fused and hardened brains. An elder brain can never have more than three active brain golems at a time. Brain golems.

Regeneration (Ex): An elder brain takes normal damage from sonic- and acid-based attacks.

Telepathic Awareness (Su): Within a radius of 350 feet, the elder brain detects all creatures whose minds are not shielded with an effect such as mind blank, even through solid rock. Within this same range, it can communicate with any creature that has a language.

An elder brain uses its quickened spell-like abilities in the same round that it makes melee attacks with its tendrils, if possible. It begins a combat against multiple foes with a mind blast.