Hydra
Ravenous Multi-headed Serpent of Legend
The Hydra is a being of pure chaos, aggression, and hunger, born when raw chaos leaked into fetid marshlands, entangling lizards and snakes alike and fusing them into a true monstrosity. The writhing and twisting flesh of these festering, multi-headed abominations constantly reforms and regrows new voracious maws hellbent on consumption.
A hydra corrupts the land around its lair. Fish float belly-up in its waters. Crops fail within a mile. Livestock develop madness and refuse to drink from any stream that flows from hydra territory. Livestock and wildlife alike birth two-headed mutant offspring.
Those who have seen a hydra and lived speak in hushed whispers: five serpentine necks writhing in patterns that hurt to watch, each crowned with a skull-sized maw dripping acid capable of melting armor and stone alike. They speak of a chorus of hisses that echoes for miles through the fog. And they speak of the terrible truth: you cannot kill what grows stronger from every wound. Even the creature's blood is so corrosive that severing a head sprays everyone nearby with melting death, only for the severed head to regrow even stronger.
Hydra Lore
- Hydras were born when raw chaos leaked into fetid marshlands, fusing serpents and lizards into regenerating abominations
- A hydra's mere presence corrupts the land for miles: crops wither, waters turn toxic, livestock birth two-headed offspring
- Desperate villages offer monthly sacrifices of livestock to hydras, hoping appeasement will spare their farms from the creature's hunger
- Alchemists and mad wizards hunt hydras for their regenerative blood. Those who survive the harvest can create potions of miraculous healing or horrifying mutation
Hydra Tactics
- The hydra wades into melee, making one bite attack per head - heroes who try to flee suffer devastating opportunity attacks from multiple heads
- When surrounded or outnumbered, the hydra unleashes Fearsome Roar or Serpentine Hiss to scatter frightened foes, then capitalizes with opportunity attacks as they flee
- The Hydra uses Toxic Breath: Blinding Sickness or Toxic Breath: Mindfire to afflict those who fail multiple saves, crippling spellcasters and archers
- Smart heroes cauterize severed heads with fire or acid to prevent the regrowth ability - otherwise each wound makes the hydra deadlier
- The Foulblood Hydra uses Cursed Wounds to reduce maximum hit points and potentially raise slain heroes as zombie thralls
- When bloodied, the Foulblood Hydra triggers Bestial Rampage to reposition without provoking attacks, then uses legendary actions to Charger and maintain relentless pressure
Hydra Statblocks
Hydra
An unkillable monstrosity of five writhing heads consumed by malice, aggression, and hunger.
Hydra
Summoned with Foe FoundryHuge Monstrosity (Hydra)
AC 16 Initiative +5 (15)
HP 178 (17d12 + 68)
Speed 40 ft., swim 40 ft.
| Mod | Save | ||
|---|---|---|---|
| Str | 20 | +5 | +5 |
| Dex | 14 | +2 | +2 |
| Con | 18 | +4 | +4 |
| Mod | Save | ||
|---|---|---|---|
| Int | 10 | +0 | +0 |
| Wis | 12 | +1 | +4 |
| Cha | 9 | -1 | -1 |
Skills Perception +7
Resistances Acid
Immunities Blinded, Charmed, Deafened, Frightened, Stunned, Unconscious
Senses Darkvision 60 ft., Passive Perception 17
CR 8 (3,900 XP; PB +3)
Traits
Cauterize. When the hydra takes Acid, Fire, or Cold damage, it must make a DC 15 Constitution saving throw. On a failed save, it cannot regain hitpoints until the end of its next turn.
Multi-Headed. The hydra has five heads. It can make as many Opportunity Attacks as it has heads.
Regrowth. At the start of its turn, if the hydra's Severed Head reaction triggered last turn, it heals 20 hitpoints. If it healed, it generates two new heads.
Actions
Multiattack. The hydra makes one attack for each of its heads.
Flesh-Dissolving Bites. Melee Weapon Attack: +8 to hit, reach 5ft., one target. Hit 9 (1d8 + 5) piercing damage and 2 (1d4) acid damage. On a hit, the target is Grappled (escape DC 14). On a hit, the target must make a DC 16 Constitution saving throw or become Poisoned until the end of its next turn.
Tear Apart. The hydra rips at a target it is grappling, releasing the grapple. The creature must make a DC 14 Strength saving throw, taking 44 (8d10) slashing damage on a failure and half as much on a success. If this damage reduces a creature to 0 hit points, it dies and is torn in half.
Reactions (One Per Head)
Severed Head. When the hydra takes 20 or more damage from an attack and has at least two heads, one of its heads is severed. Each other creature in a 10 foot emanation must make a DC 16 Dexterity saving throw, taking 12 (5d4) acid damage on a failed save. The hydra may use its Regrowth ability at the start of its next turn.
Foulblood Hydra
When a hydra consumes sufficient demonic flesh, it becomes infected with demonic ichor. Its blood becomes infected with black ichor and it becomes a true malignant curse upon the land.
Foulblood Hydra
Summoned with Foe FoundryHuge Monstrosity (Fiend*, Hydra)
AC 18 Initiative +10 (20)
HP 287 (23d12 + 138)
Speed 40 ft., swim 40 ft.
| Mod | Save | ||
|---|---|---|---|
| Str | 22 | +6 | +10 |
| Dex | 14 | +2 | +2 |
| Con | 22 | +6 | +10 |
| Mod | Save | ||
|---|---|---|---|
| Int | 11 | +0 | +0 |
| Wis | 12 | +1 | +5 |
| Cha | 9 | -1 | -1 |
Skills Stealth +6, Perception +9
Resistances Acid
Immunities Blinded, Charmed, Deafened, Frightened, Stunned, Unconscious
Senses Darkvision 60 ft., Passive Perception 19
CR 12 (8,400 XP; PB +4)
Traits
Black Blood. When the hydra takes piercing or slashing damage, it splashes nearby creatures with black ichor. Each non-demon creature within 10 feet takes 4 Acid damage and its movement speed is halved until the end of its next turn. This ability activates only once per turn.
Cauterize. When the hydra takes Acid, Fire, or Cold damage, it must make a DC 15 Constitution saving throw. On a failed save, it cannot regain hitpoints until the end of its next turn.
Multi-Headed. The hydra has five heads. It can make as many Opportunity Attacks as it has heads.
Regrowth. At the start of its turn, if the hydra's Severed Head reaction triggered last turn, it heals 20 hitpoints. If it healed, it generates two new heads.
Legendary Prowess (3/day). The hydra can choose to succeed on a saving throw or ability check instead of failing. When it does so, it takes 15 force damage.
Actions
Multiattack. The hydra makes one attack for each of its heads.
Flesh-Dissolving Bites. Melee Weapon Attack: +10 to hit, reach 5ft., one target. Hit 10 (1d8 + 6) piercing damage and 2 (1d4) acid damage.
Flesh Melting Breath (Recharge 5-6). The hydra breathes acid in a 60 ft cone. Each creature in the area must make a DC 18 Dexterity save. On a failure, the creature takes 40 (9d8) acid damage or half as much on a success. Additionally, creatures that fail by 5 or more are Burning [10 (4d4) acid]. While burning this way, the creature is also Poisoned. A burning creature suffers 10 (4d4) ongoing acid damage at the end of each of its turns. A creature may use an action to end the condition.
Bonus Actions
Cursed Wounds. Immediately after hitting with an attack, the hydra converts all of that attack's damage to necrotic damage and forces the target to make a DC 18 Charisma save. On a failure, the target is cursed and its maximum hit points are reduced by the necrotic damage taken. The target dies and reanimates as a Zombie under the control of the hydra if this damage leaves it with 0 hit points.
Feeding Frenzy. The hydra moves up to 30 feet without provoking opportunity attacks. If it ends the movement next to a target that has lost half its hit points or more, it may make an attack against that target.
Reactions (One Per Head)
Severed Head. When the hydra takes 20 or more damage from an attack and has at least two heads, one of its heads is severed. Each other creature in a 10 foot emanation must make a DC 18 Dexterity saving throw, taking 15 (6d4) acid damage on a failed save. The hydra may use its Regrowth ability at the start of its next turn.
Legendary Actions (3)
Charge. The hydra moves up to half its speed and makes an Flesh-Dissolving Bites attack.
Flesh Melting Breath. The hydra uses or attempts to recharge its Flesh Melting Breath ability. It can't take this action again until the start of its next turn.
Replenish. The hydra gains 10 temporary hitpoints. It can't take this action again until the start of its next turn.
Hydra Encounter Ideas
Hydra encounters blend immediate survival threats with environmental hazards, from ambushes in fetid swamps to cultist rituals gone wrong.
- While navigating a fetid swamp the party rests on a small island covered in reeds that is actually a Hydra's five heads resting on its submerged body. The island begins to shift and heave as the hydra awakens.
- As the party crosses a rickety causeway through the mist-shrouded swamp, drops of acid begin to fall all around and dissolve the bridge supports as five hissing Hydra heads encircle the PCs
- Robed Cultists chant around a chained Hydra, throwing bound prisoners into its reach. The hydra has been starved and driven mad. The cultists use its acidic blood in rituals.
- A Foulblood Hydra drags the mutilated corpse of an Ogre back to its lair to feast. The ogre wears a gleaming golden crown stuffed onto one of its fat fingers as a crude ring.
Hydra Adventure Ideas
Hydra adventure hooks explore the far-reaching consequences of these unkillable monsters, from capture missions to investigating corrupted lands.
- The PCs are hired by a half-crazed but rather wealthy circus owner to capture a Hydra alive. He foolishly plans to show off the beast at an upcoming festival.
- Priests report that a sacred spring has fouled, turning black and toxic. The source lurks in a sunken temple upstream - a Foulblood Hydra whose black ichor corrupts the sacred stream and drives pilgrims mad.
- An ambitious Duke hires the PCs, along with multiple other competing adventuring parties, to slay the legendary Hydra of Five Crowns. Legends say the beast once devoured five kings gathered for an important assembly and now wears their glittering magical crowns.
- The PCs are asked to investigate why livestock in a small farming village have recently been born with multiple twisted, mutated heads, caused by the corrupting presence of a Foulblood Hydra that has taken up a lair in a nearby sunken dungeon. The villagers, led by a zealous Priest, blame a local soothsayer.
Frequently Asked Questions
How many heads does a hydra have in D&D 5E?
A standard Hydra in D&D 5E has five heads. Each head can make a separate bite attack, allowing the hydra to attack five times per turn. When a head is severed, the hydra's regeneration ability typically causes two new heads to grow back in its place, making the creature even more dangerous as combat progresses.
How do you kill a hydra in 5E?
To permanently kill a Hydra, you must prevent its regeneration granted by its Hydra Heads power. When you deal damage to a hydra's head, use fire or acid damage to Hydra Heads the wound and prevent regrowth. Without cauterization, severed heads regrow stronger. Focus damage on the body while using fire spells or flaming weapons to stop the head regeneration mechanic.
What CR is a hydra in D&D?
Hydras typically range from CR 5 to CR 10 depending on the variant. A standard five-headed hydra is usually CR 8, making it a deadly challenge for a party of 3rd to 5th level adventurers. More powerful variants like the Foulblood Hydra with legendary actions and cursed abilities can reach CR 10 or higher.
Can a hydra regrow its heads in 5E?
Yes, hydra head regeneration is a core mechanic. When a hydra takes 20 or more damage from an attack, one head is severed. At the start of its next turn, if a head was severed last turn, the hydra heals 20 hitpoints and grows two new heads. This means the hydra can become progressively more dangerous if players don't prevent the regeneration.
What is a hydra's weakness in D&D?
Fire, acid, and cold damage are a hydra's primary weaknesses. When a hydra takes these damage types, it must make a Constitution saving throw or be unable to regain hitpoints until the end of its next turn. This is crucial for defeating the creature, as it prevents the hydra from healing when it would otherwise regrow heads. Smart parties bring alchemist's fire, fire spells, or acid flasks to exploit this vulnerability.
Where do hydras live in D&D?
Hydras dwell in fetid swamps, toxic marshlands, and murky bogs. Their presence corrupts the surrounding environment, causing crops to fail, waters to turn acidic, and livestock to birth mutant two-headed offspring. They prefer waterlogged lairs where they can ambush prey and submerge their massive bodies while keeping their heads above water.
What level should you fight a hydra?
A standard CR 8 hydra is appropriate for a party of four 5th-level characters as a hard encounter, or 4th-level characters as a deadly boss fight. Extremely capable or well-geared parties should be at least 3rd level with access to fire or acid damage sources.
Are there legendary hydra variants for boss encounters?
Yes! The Foulblood Hydra is a legendary boss variant created when a hydra consumes demonic flesh, becoming infected with malignant black ichor. This CR 10+ monstrosity features legendary actions, legendary resistance, and devastating abilities like Cursed Wounds that reduce maximum hit points and can raise slain heroes as zombie thralls. The Foulblood Hydra also gains Bestial Rampage when bloodied, allowing it to reposition without provoking opportunity attacks and maintain relentless pressure through legendary Charger actions. This makes it an ideal climactic boss for mid-tier campaigns centered around stopping a corrupting force that threatens entire regions.