Neutral Large Monster (reptile) (20-ft long)
FREQUENCY: Uncommon
NO. APPEARING: 1 (IV. 1)
SURPRISE: 33%
SENSES: infravision, all-around sight
ARMOR CLASS: 5
MOVE: 9"
HIT DICE: 5 (hp 8 per head)
% IN LAIR: 20%
TREASURE TYPE: B
ATTACK AC 0: 15
MELEE: 4 bites (1d6 primary) and 1 bite (1d6 iterative)
SPECIAL ATTACKS: multi-attack - Hits As: +1
SPECIAL DEFENSES: multi-headed, immune to weapon damage (body)
MAGIC RESISTANCE: Standard
INTELLIGENCE: Semi- (2-4)
MORALE: +25%
SAVES: Poison 11, Petrify 12, Wand 13, Breath 13, Spell 14
LEVEL: IV (XP 205)
Hydrae are gray brown to blackish brown with lighter underbellies tinged towards yellow or tan. Their eyes are amber to orange. The teeth are yellowish white.
6-headed (6 HD): THAC0: 13; Damage: 1d6 per head; Hits As: +1; MORALE: +30%; SAVES: Poison 11, Petrify 12, Wand 13, Breath 13, Spell 14
7-headed (7 HD): THAC0: 13; Damage: 1d8 per head; Hits As: +2; MORALE: +35%; SAVES: Poison 10, Petrify 11, Wand 12, Breath 12, Spell 13
8-headed (8 HD): THAC0: 12; Damage: 1d8 per head; Hits As: +2; MORALE: +40%; SAVES: Poison 10, Petrify 11, Wand 12, Breath 12, Spell 13
9-headed (9 HD): THAC0: 12; Damage: 1d8 per head; Hits As: +3; MORALE: +45%; SAVES: Poison 8, Petrify 9, Wand 10, Breath 9, Spell 11
10-headed (10 HD): THAC0: 10; Damage: 1d8 per head; Hits As: +3; MORALE: +50%; SAVES: Poison 8, Petrify 9, Wand 10, Breath 9, Spell 11
11-headed (11 HD): THAC0: 10; Damage: 1d10 per head; Hits As: +4; MORALE: +55%; SAVES: Poison 7, Petrify 8, Wand 9, Breath 8, Spell 10
12-headed (12 HD): THAC0: 9; Damage: 1d10 per head; Hits As: +4; MORALE: +60%; SAVES: Poison 7, Petrify 8, Wand 9, Breath 8, Spell 10
Hydrae are reptilian monsters found in marshes, swamps, and similar places, as well as in subterranean lairs.
Their large, four-legged bodies are surmounted by from 5 to 12 heads (roll an 8-sided die to determine number). Each head has 1 hit die of a full 8 hit points. When all of a hydra's heads are killed, the body dies, but not until each and every head is killed.
The hydra attacks according to the number of heads it has, each head being considered as a hit die. Thus, a hydra of 7 heads attacks as a monster of 7 hit dice.
It is possible for the hydra to attack several opponents at once, and up to 4 heads are able to attack the same target simultaneously.
Damage scored is based on the number of heads the hydra has: hydrae of 5 or 6 heads do 1-6 hit points of damage/attack, those with 7 to 10 heads score 1-8 points of damage, and hydrae with 11 or 12 heads do 1-10 hit points of damage.
Lernaean Hydra. These creatures are very rare. The lernaean hydra is indistinguishable from a normal hydra until it is attacked.
Every time one of the heads of these creatures is cut off or killed, it grows two new ones in 1-4 melee rounds unless fire is applied to the dead member or neck stump.
Thus, a 5-headed lernaean hydra could grow to a 12-headed monster in a single combat, gaining the appropriate hit dice and attack potential in the process.
Pyrohydra. Pyrohydrae also appear quite similar to normal hydrae, although their coloration may be tinged with more red. They seldom exceed 7 heads, 10% having 8, and no 9-headed pyrohydra has ever been recorded.
Each head of a pyrohydra is able to breathe fire twice per day, the breath shooting out in a cone ½" diameter at the mouth, 1" diameter at the end, and 2" long. This fire causes 8 hit points of damage (4 if saving throw versus dragon breath is made).
They can, of course, strike normally as well.