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 to slashing damage. Each head gives the hydra another attack (but not more HD, XP, or will). Axes, Long Blades, two-handed Polearms, lajatangs, and level 3 claws all cut off hydra heads.
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. If all of a hydra's heads are cut off, it dies instantly. 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. The Summon Hydra spell lets you call a friendly 4- to 12-headed hydra (depending on spell power) to fight for you, but for an extremely short time.
Tips & Tricks
- Hydras max out at 20 heads, at which point they get 20 individual melee attacks per turn. Don't let this happen.
- They have poison resistance, so poison, curare, 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 down. Do not use an edged freezing weapon, however, as heads will still grow back.
- If attempting to escape, remember that hydras cannot open doors and do not see invisible.
- Flaming edged weapons are obvious counters; they 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 the hydra less time to gnaw on you between swings. Just make sure you have the AC to survive a hydra's vicious attacks. 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: Polearms have access to spears, tridents, or demon tridents, while lajatang users can work with a quarterstaff. Axes and Long Blades users can use weapons they've cross-trained with.
- Even characters with only slashing weapons can use certain Invocations:
- Makhleb: Greater Servants or multiple lesser servants can easily kill hydras.
- Beogh: Smite works, but incurs a heavy piety cost.
- Elyvilon: Hydras are natural beasts and can be pacified easily.
- Lugonu: With high Invocations, you may be able to banish 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.
- Failing that, ranged weaponry can work well. Other than launchers, the following are easily accessible:
- 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.
- Throwing: Javelins are particularly strong with minimal investment. Ogres and trolls have access to Large Rocks, which are incredibly powerful, but their high delay makes them risky to use up close.
- Most spellcasters have an easier time with hydras. Level 3+ Conjurations of any school can kill a hydra in 3-6 hits. Enough uses of Summon Ice Beast will fell a hydra, though a hydra with a high number of heads may require more. Ice Form can slow hydras (though its AC is on the low side), while Statue Form gives you the strength and durability to fight back on even footing. However, lightly armoured casters will have a problem if a hydra comes too close; use the Blink spell, an escape item, or just run away.
- Finally, remember that you don't have to kill everything in Crawl! Going down a different staircase, escaping with a scroll of teleport, or taking a detour into the Orcish Mines are all valid options if hydras prove too tough early on.
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 will be raised with one head. In any case, you can slice their heads off, but they will never grow back regardless of brand. Note that hydra simulacra can have horrifyingly high damage output if you lack cold resistance (+13-38 cold damage per head). Spectral hydras 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 wand of scattershot was 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.