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Family: Hydra

Huge dragon, chaotic evil

Armor Class 15 (natural armor)
Hit Points 230 (20d12 + 100)
Speed 30 ft., swim 30 ft.

20 (+5) 12 (+1) 20 (+5) 2 (-4) 10 (+0) 7 (-2)

Saving Throws Dexterity+7, Constitution+12, Wisdom+7, Charisma+5
Damage Immunities poison
Damage Resistances bludgeoning, piercing, and slashing from nonmagical attacks
Condition Immunities poisoned, prone
Skills Perception +24, Stealth +7
Senses darkvision 120 ft., passive Perception 34
Challenge 19 (22,000 XP)

Special Traits

  • Contamination. The hydra emits an aura of corruption 30 feet in every direction. Plants that aren’t creatures wither in the aura, and the ground in it is difficult terrain for other creatures. Any creature that starts its turn in the aura must succeed on a DC 19 Constitution saving throw or take 14 (4d6) poison damage. A creature that succeeds on the save is immune to this hydra’s Contamination for 24 hours.
  • Hold Breath. The hydra can hold its breath for 1 hour.
  • Legendary Resistances (3/Day). If the dragon fails a saving throw, it can choose to succeed instead.
  • Multiple Heads. The hydra has nine heads. While it has more than one head, the hydra has advantage on saving throws against being blinded, charmed, deafened, frightened, stunned, and knocked unconscious. Whenever the hydra takes 25 or more damage in a single turn, one of its heads dies. If all its heads die, the hydra dies. At the end of its turn, it grows two heads for each of its heads that died since its last turn, unless it has taken fire damage since its last turn. The hydra regains 10 hit points for each head regrown in this way.
  • Reactive Heads. For each head the hydra has beyond one, it gets an extra reaction that can be used only for opportunity attacks.
  • Wakeful. While the hydra sleeps, at least one of its heads is awake.


  • Multiattack. The hydra makes as many attacks as it has heads plus one to constrict.
  • Bite. Melee Weapon Attack: +11 to hit, reach 10 ft., one target. Hit: 10 (1d10 + 5) piercing damage plus 4 (1d8) poison damage.
  • Constrict. Melee Weapon Attack: +10 to hit, reach 5 ft., one Large or smaller creature. Hit: 16 (2d10 + 5) bludgeoning damage. The target is grappled (escape DC 19) if the hydra isn’t already constricting a creature, and the target is restrained until this grapple ends.
  • Poison Breath (Recharge 5-6). The dragon exhales poison in a 60-foot cone. Each creature in that cone must make a DC 15 Dexterity saving throw, taking 54 (12d8) poison damage on a failed save, or half as much damage on a successful one.
  • Tail. Melee Weapon Attack: +11 to hit, reach 15 ft., one target. Hit: 14 (2d8 + 5) bludgeoning damage.

Legendary Actions

The hydra can take 3 legendary actions, choosing from the options below. Only one legendary action option can be used at a time, and only at the end of another creature’s turn. The hydra regains spent legendary actions at the start of its turn.

  • Detect. The dragon makes a Wisdom (Perception) check.
  • Tail Attack. The dragon makes a tail attack.
  • Summon Crab (Costs 2 Actions). The hydra summons a karkinos.


What at first appeared to be multiple snakes tangled up with each other is in fact a multi-headed best, all of them connected to one large serpent body.

Hydras are reptile-like monsters with nine heads. A hydra is gray brown to dark brown, with a light yellow or tan underbelly. The eyes are amber, and the teeth are yellow-white. It is about 20 feet long and weighs about 4,000 pounds.

Deadly by Nature. Hydras are extremely poisonous, such that their blood is used in arrows to slay even more fearsome opponents. Their breath is dire enough to kill a man where he stands, but even the miasma that surrounds them can poison attackers even while the hydra sleeps.

Section 15: Copyright Notice

5E RPG: Ancient Adventures. Copyright 2020, Mal and Tal, LLC; Author Michael Tresca.

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