Crysknife

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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 (+10/positive enchant)
Weight	20
Material	mineral

The crysknife is a weapon that appears in NetHack.

Generation

Crysknives are never randomly generated, though they can appear in bones files.

Description

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). This 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 in order 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 (e.g. usually when the monster dies). The reverted worm tooth will retain the crysknife's enchantment.

Erodeproofing a crysknife will "fix" it; a fixed crysknife will only revert 10% of the time. Dropping a stack of crysknives will make a single roll for the entire stack, but throwing multiple knives will roll for each of them. A crysknife that reverts also loses its fixing.

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 now made of bone.

Strategy

The crysknife's +3 to-hit bonus and consistent d10 damage against both small and large monsters makes it a nice choice for #twoweaponing.

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. The material cost of creation and maintenance is generally prohibitive - it takes one scroll of enchant weapon to sharpen each worm tooth into a crysknife, plus one more scroll to fix the entire stack. On average, each crysknife will last 10 throws before having to be sharpened and fixed again.

In addition, most roles that can advance in knife skill have better ranged combat options. Healers are a potential exception, as they can only reach multishot 3 with knives, although magic missile is in general much more practical and potentially more powerful for them.

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	$\frac{1+10}{2}+9=\bold{14.5}$

Origin

The crysknife is from Frank Herbert's science fiction novel Dune. This includes its fabrication from worm teeth and requiring "proximity to a human body's electrical field to prevent disintegration".

Variants

SLASH'EM

SLASH'EM changes the damage for crysknives to 1d20 against small and 1d30 against large; crysknives (and worm teeth) do not stack, so it is not possible to multishot them.

Yeomen can gain basic skill with knives; Ice Mages, Flame Mages, and Necromancers can become skilled; and Healers can become expert. A Healer can benefit seriously from the crysknife; since they have little weapon choice other than darts, a crysknife could be their most lethal weapon choice.

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	$\frac{1+20}{2}+7=\bold{17.5}$	$\frac{1+30}{2}+7=\bold{22.5}$

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 ]