Mordant Hydra
Huge natural beast (reptile)
Level 18 Solo Brute XP 10000

Initiative +13        Senses Perception +17; all-around vision, low-light vision
HP 880; Bloodied 440
AC 31; Fortitude 33, Reflex 30, Will 29
Resist 15 acid
Saving Throws +5
Speed 6, swim 12
Action Points 2

(⚔) Bite (standard, at-will)

Reach 3; +21 vs AC; 1d8+6 damage.

(➶) Acid Spit (standard, at-will)

Ranged 10; +18 vs Reflex; 1d8+6 acid damage.

⚔ Hydra Fury (standard, at-will)

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

Many-Headed

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

Threatening Reach

The mordant hydra can make opportunity attacks against all enemies within its reach (3 squares).

Alignment Unaligned        Languages -
Str 22 (+15)      Dex 18 (+13)      Wis 16 (+12)
Con 24 (+16)      Int 2 (+5)      Cha 8 (+8)

Published in Monster Manual, page(s) 164.