Freezing sphere

e freezing sphere
Difficulty	8
Attacks	Explode 4d6 cold

e freezing sphere
Difficulty	8
Attacks	Explode 4d6 cold
Base level	6
Base experience	91
Speed	13
Base AC	4
Base MR	0
Alignment	0 (neutral)
Frequency (by normal means)	2 (Quite rare)
Genocidable	Yes
Weight	10
Nutritional value	10
Size	Small
Resistances	cold
Resistances conveyed	None
A freezing sphere: can fly. does not breathe. has no limbs. has no head. is mindless. does not eat. (*) is neither male nor female. is normally generated hostile. can be seen through infravision. does not appear in Gehennom. never leaves a corpse.
Reference	monst.c#line310

A freezing sphere, e, is a type of monster that appears in NetHack. It is a sphere with an affinity to cold that behaves like other spheres, and is the only one that does not emit light.

Freezing spheres possess a cold explosion attack that can shatter potions in the target's inventory, and possesses cold resistance.

The spellbook of freeze sphere is a deferred feature that teaches a spell the hero can use to create tame freezing spheres.

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

Per commit 6b60618e, freezing spheres create explosions with their attacks, which cover a 3x3 area around them and affect items and other monsters caught within the blast radius - this does not count the inventory of a hero that is polymorphed into a freezing sphere and explodes. This is adapted from xNetHack, and the sphere's difficulty rating is also raised to 9.

Generation

Randomly generated freezing spheres are always created hostile, and they will not be generated in Gehennom.

A freezing sphere does not leave a corpse upon death.

Strategy

Freezing spheres are fairly annoying to deal with, but their explosion attack can only destroy potions, making them the least hazardous to a hero's inventory. Pets that attack freezing spheres will likely take the explosion in your stead, and cold resistance completely trivializes them. Freezing spheres can also be made to miss if you are invisible or displaced, and their nonexistent MR score means they can easily be put to sleep or otherwise immobilized, allowing a hero or their pet to kill them before they can explode.

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

Per commit 9942b65d, extrinsic cold resistance protects the target's open inventory from damage by a freezing sphere explosion ⁹⁹⁄₁₀₀ of the time.

History

The freezing sphere first appears in Hack for PDP-11, which is based on Jay Fenlason's Hack, and is included in the initial bestiary for Hack 1.0—in Hack 1.21, the ice ball is a somewhat similar monster included in the bestiary.

Variants

SLASH'EM

In SLASH'EM, freezing spheres also have sleep resistance and hit as +2 weapons.

SLASH'EM makes the spellbook of freeze sphere and its spell functional: freeze spheres summoned by the spell only exist for a temporary amount of time, and monsters hit by their explosions are treated as though the hero had attacked them, e.g. awarding them experience for monsters that the sphere kills, blaming them for angering peaceful monsters, and so on. The spell also respects extinction, meaning it has a finite number of uses.

All of the above information also applies to SlashTHEM.

dNetHack

In dNetHack, notdNetHack and notnotdNetHack, freezing spheres explode on death similar to gas spores, covering a 3x3 area centered on it that can burn items in the open inventory of monsters caught in the blast; extrinsic cold resistance can prevent both effects.

Freezing spheres may also be generated in the Lawful Quest, where they will appear on the Paths of Law and within the Arcadian Tower if Oona's elemental affinity is set to cold. The summon sphere monster spell can summon freezing spheres.

xNetHack

In xNetHack, the explosion attack of freezing spheres covers a 3x3 radius, affecting monsters and items caught in the explosion as well as items in the affected monsters' inventories; extrinsic cold resistance protects the open inventory from damage ⁹⁹⁄₁₀₀ of the time.

SpliceHack

In SpliceHack, the spellbook of freeze sphere is made functional and works similar to SLASH'EM, and freezing spheres can also be created by reading a scroll of elementalism while confused. This also applies to Hack'EM.

EvilHack

In EvilHack, the spellbook of freeze sphere is made functional and works similar to SLASH'EM, and freeze spheres created with the spell are not counted towards the charisma-based limit for pets.

Freezing spheres explode on death similarly to gas spores: both their explosion attack and on-death explosions cover a 3x3 radius centered on its square, affecting monsters and items caught in the explosion.

Encyclopedia entry

Freezing spheres share the entry below with other spheres:

The attack by those who want to die -- this is the attack against which you cannot prepare a perfect defense.
                       --Human aphorism

[ The Dosadi Experiment, by Frank Herbert ]