Primordial Hydra
Gargantuan elemental beast (reptile)
Level 25 Solo Brute XP 35000

Initiative +18        Senses Perception +21; all-around vision, Darkvision
HP 1200; Bloodied 600
AC 38; Fortitude 40, Reflex 35, Will 33
Resist 20 acid, 20 fire
Saving Throws +5
Speed 8, swim 16
Action Points 2

(⚔) Bite (standard, at-will)

Reach 4; +28 vs AC; (+30 with opportunity attacks)1d10+8 damage, or 1d10 + 13 on a successful opportunity attack.

(➶) Flaming Acid Spit (standard, at-will) ✦ Acid, Fire

Ranged 10; +25 vs Reflex; 1d10+8 acid and fire damage.

⚔ Hydra Fury (standard, at-will)

The mordant hydra makes six basic attacks (any combination of bite attacks and flaming acid spit attacks).

Many-Headed

Each time the primordial hydra becomes dazed or stunned, it loses one attack on its next turn instead. Multiple such effects stack.

Threatening Reach

The primordial hydra can make opportunity attacks against all enemies within its reach (4 squares).

Alignment Chaotic evil        Languages -
Str 26 (+20)      Dex 22 (+18)      Wis 18 (+16)
Con 32 (+23)      Int 4 (+9)      Cha 12 (+13)

Published in Monster Manual, page(s) 165.