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) Crysknife.png
Name crysknife
Appearance crysknife
Damage vs. small 1d10
Damage vs. large 1d10
To-hit bonus +3
Weapon skill knife
Size one-handed
Base price 100 zm
Weight 20
Material mineral

A crysknife is a type of weapon that appears in NetHack. It is made of mineral and uses the knife skill.

The following information pertains to an upcoming version (NetHack 3.7.0). If this version is now released, please verify that it is still accurate, then update the page to incorporate this information.

The crysknife is made of bone.


Crysknives are never randomly generated, though they can appear in bones files. The weapon can only be generated using the process described below.


A crysknife can only be created normally by reading a noncursed scroll of enchant weapon while wielding a worm tooth, though it is also possible to wish for one. Reading a scroll will uncurse the worm tooth if applicable, but does not increase the enchantment - thus, it is safe to re-sharpen a tooth regardless of its enchantment. A stack of worm teeth will merge into a single crysknife, so to create multiple crysknives you must split up the stack and enchant each one individually.

If a crysknife leaves your possession, it reverts to a worm tooth - placing it in a container in your inventory will not revert it unless that container subsequently leaves your possession. If stolen by a monster, the crysknife will not revert unless it leaves their inventory, either through their death or being disarmed. A reverted worm tooth will retain the enchantment it had as a crysknife. Dropping a stack of crysknives will make a single reversion roll for the entire stack, but throwing multiple knives will roll for each of them.

Erodeproofing a crysknife will "fix" it: a fixed crysknife will only revert to a tooth 110 of the time; a crysknife that reverts also loses its fixing.


The crysknife's +3 to-hit bonus and consistent d10 damage against both small and large monsters makes it a nice choice for #twoweaponing. As the most powerful knife weapon in the game, roles such as Healers and Rogues may even consider it for a primary weapon choice.

Though crysknives count as throwing weapons and get a to-hit bonus when thrown that makes them more powerful than even the rare shuriken and cumbersome boomerang, their reversion property typically makes throwing them a bad idea: it takes several read scrolls of enchant weapon to sharpen each individual worm tooth, plus one more scroll to 'fix' the entire stack, and on average each crysknife will last 10 throws before they must be sharpened and fixed again. Most roles that can advance in knife skill have better ranged combat options: Healers in particular can reach a multishot level of 3 only by using knives, but are better off considering the magic missile spell and/or a stack of enchanted knives.

Average damage calculation

The average damage calculations in the following table do not include bonuses from weapon skills, strength, or from using a blessed weapon against undead or demons.

Weapon Average damage
+0 crysknife \frac{1+10}{2}=\bold{5.5}
+7 crysknife \frac{1+10}{2}+7=\bold{12.5}
+9 crysknife \frac{1+10}{2}+9=\bold{14.5}


The crysknife and its means of production are introduced in Hack 1.0.


In Frank Herbert's science fiction novel Dune, the crysknife is the formal and sacred weapon of the desert-dwelling Fremen. A crysknife is a personally-tuned knife with a double-edged curved blade, ground from the crystal tooth of a sandworm. The crysknife comes in two forms, fixed and unfixed: Unfixed knives need to be stored in proximity to an electrical field produced by the human body, or they will disintegrate after a period of time - which is why NetHack crysknives revert to worm teeth when they leave the user's inventory. Fixed crysknives are put through chemical processes to keep them permanently intact, which is represented by fixed crysknives in NetHack only reverting 10% of the time.



In SLASH'EM, crysknives can be poisoned, and deal 1d20 against small monsters and 1d30 against large ones. In addition to the standard method, crysknives can also be created by enchanting a worm tooth through shopkeeper services. Crysknives and worm teeth do not stack, so it is not possible to multishot them.

For Healers, the crysknife is unambiguously their best choice of standard weapon. Yeomen, Ice Mages, Flame Mages, and Necromancers may also consider a crysknife for their main weapon.

Average damage calculation

The average damage calculations in the following table do not include bonuses from weapon skills, strength, or from using a blessed weapon against undead or demons.

Weapon Small monsters Large monsters
+0 crysknife \frac{1+20}{2}=\bold{10.5} \frac{1+30}{2}=\bold{15.5}
+7 crysknife \frac{1+20}{2}+7=\bold{17.5} \frac{1+30}{2}+7=\bold{22.5}

NetHack: The Next Generation

NetHack: The Next Generation introduces the artifact crysknife Wormbiter, which is neutral-aligned and does additional physical damage to worms.


In dNetHack, the crysknife and worm tooth are made of stone. A crysknife can be poisoned and does not incur a to-hit penalty when thrown.


In addition to SLASH'EM details, SlashTHEM adds Wormbiter, which functions as it does in NetHack: The Next Generation and has +5 to-hit against worms.

Encyclopedia entry

[The crysknife] is manufactured in two forms from teeth taken from dead sandworms. The two forms are "fixed" and "unfixed". An unfixed knife requires proximity to a human body's electrical field to prevent disintegration. Fixed knives are treated for storage. All are about 20 centimeters long.

[ Dune, by Frank Herbert ]