Myrmyxicus (CR 21)
Huge Outsider (Aquatic, Chaotic, Evil, Extraplanar, and Tanar'ri)
Alignment: Always chaotic evil
Initiative: +2 (Dex); Senses: Listen +30 and Spot +30
Languages: Telepathy 100 ft.
AC: 33 (-2 size, +2 Dex, +18 natural, +5 profane), touch 15, flat-footed 31
Hit Dice: 18d8+126 (207 hp); DR: DR 15/good and iron
Fort +18, Ref +13, Will +18
Speed: 20 ft., fly 40 ft. (poor), swim 60 ft.
Space: 15 ft./15 ft.
Base Attack +18; Grapple +37
Attack: Huge +3 unholy scythe +27 melee
Full Attack: Huge +3 unholy scythe +27/+22/+17/+12 melee and 3 Huge +3 unholy scythes +22 melee, or bite +25 melee and tail +25 melee and 6 tentacles +25 melee
Damage: Huge +3 unholy scythe 2d6+14/19-20/x4 primary), Huge +3 unholy scythes 2d6+8/19-20/x4 (secondary), bite 2d8+5, tail 1d8+5, tentacle 1d6+5
Special Attacks: Breath weapon, Charisma drain, constrict 1d6+5, improved grab, spell-like abilities, summon Tanarri
Abilities: Str 33, Dex 15, Con 24, Int 22, Wis 24, Cha 21
Special Qualities: infuse scythe, outsider traits, SR 30, Tanarri traits, unholy ichor
Feats: Alertness; Cleave; Improved Critical (scythe); Multiattack; Multiweapon Fighting; Power Attack; Weapon Focus (scythe)
Skills: Bluff +26, Concentration +29, Diplomacy +30, Disgraise +5 (+7 acting), Hide +15, Intimidate +28, Knowledge (arcana) +27, Knowledge (religion) +27, Knowledge (the planes) +27, Listen +30, Search +27, Sense Motive +28, Spellcraft +29, Spot +30, Survival +7 (+9 following tracks or on other planes), and Swim +40
Advancement: 19-25 HD (Huge); 26-48 (Gargantuan); 49-54 (Colossal)
Climate/Terrain: Any water (Abyss)
Organization: Solitary
Treasure/Possessions: Standard coins, double goods, standard items
Source:
Fiend Folio
The Abyss holds an incredible diversity of demons. These evil denizens come in many forms with varied abilities. These creatures fight and manipulate each other, each striving for personal autonomy even as they seek to subjugate others. When not in conflict among themselves, demons battle various forces of good as well as the lawful evil inhabitants of the Nine Hells.
The largest and most diverse group of demons is the tanar'ri, unchallenged masters of the Abyss.
The devastating and terrible myrmyxicuses are among the most powerful of the tanar'ri. They are feared and respected by most anything they encounter.
A myrmyxicus is a truly terrifying sight. Its greasy green body is eellike, measuring nearly 25 feet in length. A tall row of spines runs down its back, and the rip of its tail is adorned with a slavering lamprey mouth. The myrmyxicus has a powerfully muscled humanoid torso with four arms arranged symmetrically around the chest. Six octopoid tentacles are arranged in a similar manner around the creature's waist, where its torso turns into its long eel-like tail. The head of a myrmyxicus resembles that of a prehistoric sea reptile, with a fanged snout and tiny black eyes, but with the addition of three pairs of curling horns like those of a ram.
The myrmyxicuses rule vast regions of the Abyssal oceans from floating citadels made of millions of tons of fish skeletons and razor-sharp shells and coral. They are their own masters, and they never serve any other creature for long. Many myrmyxicuses spend ages looking for ways to transport their floating citadels into the seas of other Abyssal layers or even other planes to expand their enslaved empires.
Combat
Unlike most powerful tanar'ri, the myrmyxicus does not have a huge array of spell-like powers to rely upon. Not that it needs such powers; in combat, few creatures can match the horrible fury of an enraged myrmyxicus. It spreads its attacks out among any creatures it can affect, only focusing its attacks on a single target in the rare case when it meets a creature that poses a challenge.
Breath Weapon (Su): Once per minute, a myrmyxicus can exhale a 40-foot cone of unholy black vapor. All creatures in this area must make a Reflex save (DC 26) or become nauseated. Good-aligned creatures take 10d6 points of unholy damage as well (this damage is halved if the Reflex save is successful). Each round beyond the first that a good-aligned victim remains in contact with the vapor, he automatically takes 5d6 points of unholy damage. The vapor remains in the area for 1d6 rounds before it dissipates.
Charisma Drain (Su): An individual struck by a myrmyxicus's tail attack must make a Will save (DC 24) of permanently lose 1d6 points of Charisma (twice that amount on a critical hit). The myrmyxicus heals 5 points of damage (10 on a critical hit) whenever it drains Charisma, gaining any excess as temporary hit points.
Constrict (Ex): With a successful grapple check, a myrmyxicus can constrict a grabbed opponent, dealing 1d6+5 points of bludgeoning damage.
Improved Grab (Ex): If a myrmyxicus hits an opponent that is at least one size category smaller than itself with a tentacle attack, it deals normal damage and attempts to start a grapple as a free action without provoking an attack of opportunity (grapple bonus +37). If it gets a hold, it also constricts on the same round. Thereafter, the myrmyxicus has the option to conduct the grapple normally, or simply use its tentacle to hold the opponent (-20 penalty on grapple check, but the myrmyxicus is not considered grappled).
Spell-like Abilities: At will - cause fear, charm person, charm monster, freedom of movement, telekinesis, teleport without error (self plus maximum load of objects only), true seeing; 3 day - control water, control weather, greater dispelling, unholy blight. Caster level 18th; save DC 15 + spell level.
Summon Tanar'ri (Sp): Once per day, a myrmyxicus can attempt to summon either 2d6 skulvyns or 1 hezrou (myrmyxicus's choice), with a 55% chance of success.
Infuse Scythe (Su): A myrmyxicus can infuse any masterwork scythe it touches with unholy magical energies, transforming it into a +3 unholy scythe as long as the demon remains in physical contact with the scythe. A myrmyxicus may infuse up to four scythes at a time in this manner; most carry four huge masterwork scythes with them for this purpose. The act of infusing a scythe is a full-round action, and the myrmyxicus may only infuse one scythe at a time. Unholy Ichor (Su): The thick, tarlike blood of a myrmyxicus sprays upon any creature that deals damage to the demon with a melee attack using a piercing or slashing weapon or natural weapon. A Reflex save (DC 26) allows the attacker to avoid the spray; otherwise he becomes nauseated for 1d4 rounds. Good-aligned creatures struck by this ichor who fail their saves take 2d6 points of unholy damage from the initial contact.
Skills: A myrmyxicus has a +8 racial bonus on any Swim check to perform some special action or avoid a hazard and can always choose to take 10 on Swim checks, even if distracted or endangered.
Outsider Traits: A demon has darkvision (60-foot range). It cannot be raised or resurrected (though a wish or miracle spell can restore life).
Tanar'ri Traits: Tanar'ri can communicate telepathically with any creature within 100 feet that has a language. A tanar'ri is immune to electricity and poison, and it has acid resistance 20, cold resistance 20, and fire resistance 20.