For a list of all reptiles, see list of reptiles and amphibians.
| A great and nightmarish lacertilian beast. It has many heads, and the potential to grow many more!
Hitting it with any bladed weapon bigger than a short blade risks lopping a head off, which, considering hydras' unique biology, is not what you want. Even a troll's claws are long enough to do the same. Only a weapon branded with flame will cauterize the wound and prevent more heads from growing.
“On the other hand, Confucius is made to say to his disciples, ‘I know how birds can fly, how fishes can swim, and how animals can run. But the runner may be snared, the swimmer may be hooked, and the flyer may be shot by the arrow. But there is the dragon. I cannot tell how he mounts on the wind through the clouds, and rises to heaven. Today I have seen Lao-tsze, and can only compare him to the dragon.’”
Hydras are notoriously dangerous melee monsters found most often in the Lair and the Swamp. They begin life with 4-8 heads, but grow two more and heal significantly whenever they lose one. This usually happens when someone deals slashing damage to it. Any such attack that deals 1-3 damage has a 50% chance of removing a head, while 4+ will always do so. Careless use of claws, axes, and long blades can result in prolonged and deadly combat.
Fortunately, there are ways to hurt them without them growing stronger. Blunt and piercing weapons injure them as normal, and flaming edged weapons will remove heads and cauterize the wound, preventing the normal regrowth. Ranged weapons and spells also function without issue. Note that the rules about edged weapons, flaming edged weapons, and blunt weapons apply to everyone who attacks a hydra, including summons and all other monsters.
Hydras cannot fly, but they swim quickly through water. Lava will effectively stop them, however.
Tips & Tricks
- Hydras with additional heads only get more attacks per turn, not more HD, XP, or MR.
- Hydras max out at 20 heads, at which point they get 20 individual melee attacks per turn. Don't let this happen.
- If you manage to get a hydra to 0 heads, it dies instantly regardless of how much HP it had left.
- The Summon Hydra spell lets you call a friendly 4-9 headed hydra to fight for you, but only for a brief time.
- They have poison resistance, so poison and Mephitic Cloud won't work.
- Hydras are cold-blooded, so cold damage (either from a weapon of freezing or Ice Magic) has a chance to slow them. Do not use an edged freezing weapon, however, as cold damage won't prevent head regrowth.
- If attempting to escape, remember that hydras cannot open doors nor see invisible.
- Here are some tips for edged-weapon users:
- Use a flaming weapon to not only avoid regrowth and healing, but to reduce the hydra's damage output with each hit. Generally, faster weapons work better for this purpose, as they give they hydra less time to gnaw on you between swings. However, most characters are unlikely to have found multiple flaming weapons by the time they reach the Lair -- use whatever you have.
- Use a non-edged weapon of the same skill, such as:
- Maces and Flails: Not an issue.
- Short Blades: All short blades deal piercing damage. Fighting a hydra with a dagger is still not recommended unless you have Stabbing bonuses. Invisibility is quite useful here, since they neither see nor sense it.
- Polearms: Use a spear, trident, or demon trident.
- Staves: Use a quarterstaff or enhancer staff.
- Axes and Long Blades: There are no safe options. Use spells, wands, or a weapon type you've crosstrained with. (High AC, berserking, and other buffs also help.)
- Unarmed Combat: Only characters with Claws 3 are at risk of severing heads. Ghouls and Felids only have one level of claws, but Trolls will have to find another way. A potion of lignification can work well.
- Makhleb: Greater Servants can easily kill hydras.
- Beogh: Smite works, but it costs piety.
- Elyvilon: Hydras are natural beasts, and can be pacified easily.
- Lugonu: With high Invocations, you may be able to send hydras to the Abyss.
- Qazlal: Blasting hydras with Upheaval works, though it chews through piety quickly.
- Trog/Berserker: Summoning one or two Ogres to pound them to a pulp is a perfectly viable option, and even the high HD Trolls can usually kill them in a few shots regardless of their heads.
- Conjurations: Most level 3+ Conjurations can kill a hydra in 3-6 hits, and even level 2's can soften them up significantly with enough time.
- Summonings: 4-7 ice beasts can easily kill a hydra, though a hydra with a high number of heads may require more.
- Transmutations: Use Ice Form or unarmed Statue Form. Spider Form also does not remove heads, but is generally less effective than Ice or Statue Form.
- Attack wands: Even at low Evocations, a wand of iceblast or wand of acid can usually kill a hydra in 2-5 hits. This is a safe course of action for most characters.
The following methods do not work:
- Polymorph: Hydras have high HD, and often turn into even tougher monsters. Storm dragons are a particularly common result.
- Low-Skill Ranged Weapons: Hydras regenerate quickly; any method which relies on whittling down its HP will likely fail.
- Stair dancing: Climbing up or down stairs next to a hydra will give it a few free hits, which is possibly all it needs to kill you.
- Berserk With an Edged Weapon: While you may be able to deal more damage than the hydra can heal per hit, its damage output will be growing, and ending your berserk slowed and wounded next to an even stronger hydra than you started with is not ideal.
- Haste, when in the Swamps: Hydras' speed advantage in water will mean you probably cannot outrun them.
Hydra corpses that are raised as zombies, skeletons, or simulacra will have the same number of heads as the corpse; zero-headed corpses cannot be raised in this way. In any case, you can slice their heads off as with normal hydras, but they will never grow back, even if a non-flaming weapon is used. Note that hydra simulacra can have horrifyingly high damage output if you lack cold resistance (+13-38 cold damage per head).
Spectral hydras created with Death Channel will have the same number of heads as the hydra when it died, but these can't be cut off.
Any of these undead hydras can be found as enemies throughout the dungeon, especially in the pestilence ending of the Swamp.
- Prior to 0.25, the now obsolete Wands of scattershot were particularly effective in killing them, as hydras have 0 AC.
- Prior to 0.20, the Captain's Cutlass dealt slicing damage and chopped hydra heads.
- As of 0.16, short swords and rapiers deal piercing damage, meaning they no longer remove heads.
- Prior to 0.12 hydras were not cold-blooded creatures, except the Lernaean hydra.