This is inspired by the hydras in the Monster Manual, but is essentially a new creature.
Infinity Hydra CR 220
Neutral Titanic Magical Beast (Extraplanar)
, Senses ; ; darkvision 60 ft.
AC 486, touch 86, flat-footed 471 (-16 size, +15 Dex, +400 natural, +32 luck, +32 insight, +13 deflection); Miss Chance 50%
hp 107900 (200d1000+7800 HD); DR 1000/brilliant energy or incorporeal
Immune fire, cold; SR 274
Melee 4 Bites +292 melee (8d6+82/17-20/x2 + 1d6 + Fort DC 151 or die) (and see text: Infinite Heads)
Base Atk +200;
Space 180 ft.; Reach 120 ft.
Atk Options Power Attack
Special Actions breath weapons, cancellation field, infinite heads, overwhelming strength, storm of countless fangs
Abilities, , , , ,
SQ fast healing 1000, flawless fortune, interdimensional insight, nebulous, slipstream
Feats Cleave, Devastating Critical (bite), Dire Charge, Great Cleave, Greater Power Attack, Improved Critical (bite), Improved Initiative, Lightning Reflexes, Overwhelming Critical (bite), Perfect Health, Power Attack, Power Attack Mastery, Superior Initiative, Weapon Focus (bite). Divine Abilities from Feats: Greater Critical, Perfect Initiative, Superior Power Attack. Cosmic Abilities from Feats: Unearthly Power Attack.
Skills Survival +140
Environment Muzaloth, the eighth dimension
Organization Solitary (unique)
The progenitor of all hydras and the ultimate predator of the dimensions. The fearful truth behind the myth of the World Tree.
The Infinity Hydra is an enormous monster whose heads and necks wind through all time and space, through multiple universes.
Breath Weapon (Su): Each head of the Infinity Hydra can breathe a line of force 2100 feet long, dealing 200d10 (average 1100) damage (Reflex DC 203 half). Alternately, all heads combined can breathe a line of gravitic force 2100 feet long, dealing 4d6% of the maximum hit points of creatures affected as damage. When 16 heads are active, all the heads can breathe a cone of astro energy 1050 feet long; all creatures caught in the cone have a 25% chance of being totally erased from reality. Breath weapons can be used at will.
Cancellation Field (Su): The Infinity Hydra radiates this gray, numbing energy in a 2100-foot radius. It has three effects. First, all creatures within the field lose the benefit of all their feats for as long as they remain within the field, but not divine or better abilities the feats were prerequisites for (as the cosmic ability Nullification). Second, it acts as an antimagic field that does not affect the Infinity Hydra's own supernatural or spell-like abilities. Finally, all foes of the Infinity Hydra suffer a -32 null penalty to armor class; attack rolls; checks (ability checks, caster level checks, skill checks, turning checks); difficulty class (for any special abilities, spell-like abilities, spells); initiative; saving throws and spell resistance.
Infinite Heads (Ex): The Infinity Hydra has a theoretically infinite number of heads, but they are distributed throughout all the universes on its immaterial, transcosmic necks. When in combat, it draws its attention to the point of threat, and so the number of heads the Infinity Hydra can attack with (and thus its number of bite attacks and force breath weapons) doubles each round; when encountered, it has 4 active heads. As more heads become active, the Infinity Hydra can use more breath weapons. Every second round this occurs, the Infinity Hydra is treated as having gained a virtual size category as well, for the purposes of damage only. The Hydra receives none of the other benefits of virtual size categories.
Overwhelming Strength (Ex): The Infinity Hydra adds double its Strength bonus to melee damage.
Storm of Countless Fangs (Ex): As a full attack action, the Infinity Hydra can use two bite attacks against all creatures within 2100 feet.
Damage Reduction (Su): Only brilliant energy weapons, ghost touch weapons, or the attacks of incorporeal creatures penetrate the Infinity Hydra's damage reduction.
Flawless Fortune (Ex): The Infinity Hydra adds a +32 luck bonus to armor class; attack rolls; checks (ability checks, caster level checks, skill checks, turning checks); difficulty class (for any special abilities, spell-like abilities, spells); initiative; saving throws and spell resistance.
Interdimensional Insight (Ex): The Infinity Hydra adds a +32 insight bonus to armor class; attack rolls; checks (ability checks, caster level checks, skill checks, turning checks); difficulty class (for any special abilities, spell-like abilities, spells); initiative; saving throws and spell resistance.
Nebulous (Ex): Attacks, spells, and effects against the Infinity Hydra have a 50% miss chance.
Slipstream (Ex): The Infinity Hydra cannot be undermined through time travel.
Divine Abilities: - Greater Critical: The Infinity Hydra's bite's critical threat range increases to 17-20. Perfect Initiative: The Infinity Hydra always goes first.
Cosmic Abilities: - Unearthly Power Attack: For every point subtracted from its attack roll, the Infinity Hydra adds four points to damage.