Flaming sphere

e flaming sphere
Difficulty	9
Attacks	Explode 4d6 fire

e flaming sphere
Difficulty	9
Attacks	Explode 4d6 fire
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	fire resistance
Resistances conveyed	fire resistance
A flaming sphere: can fly. does not need to 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. never leaves a corpse. gives out light.
Reference	NetHack 5.0.0 - include/monsters.h, line 350

A flaming sphere, e, is a type of monster that appears in NetHack. The flaming sphere is a fiery sphere monster that emits light in a 1-square radius around itself, and can burn through webs while moving.

A flaming sphere has a fire explosion attack that causes them to self-destruct and cover a 3x3 square radius centered on their position, which deals 4-24 base damage to a hero or any other monsters caught in the explosion: this can burn armor and has a chance of destroying scrolls, spellbooks, potions, and globs of green slime on the floor and in the inventory of anyone caught in the blast, with the amount of items affected being equal to ¹⁄₅ of the fire damage that was dealt—a hero or monster with a source of extrinsic fire resistance has a ⁹⁹⁄₁₀₀ chance per item of preventing their inventory from burning. Flaming spheres possess fire resistance.

The spellbook of flame sphere is a deferred item that teaches a spell the hero can use to create tame flaming spheres.

Killing a flaming sphere with a digestion attack can grant fire resistance to the digesting hero or monster.

Generation

Randomly generated flaming spheres are always created hostile.

A flaming sphere does not leave a corpse upon death.

Strategy

The following information pertains to a recently-released stable version (NetHack 5.0.0) and will be subject to revision as strategy is developed and bugs are discovered and/or fixed.

Explosion attack changes and item destruction refactoring have significant ramifications.

Flaming spheres are fairly annoying at best to deal with, due to the amount of inventory damage they can inflict: their movement speed of 13 makes them more likely to catch an unhasted hero, and pets that attack flaming spheres will likely trigger the explosion themselves and catch you or other pets and monsters in the crossfire. While invisibility and displacement can fool a flaming sphere into exploding prematurely, there is a chance the hero may still be caught in the explosion.

If a flaming sphere is approaching, it may be wise to quickly stash or drop any loose flammable items that are on hand before it can close in—keep away from any ice without a means of flight, levitation or water walking, since the sphere's explosion risks causing you to drown. An extrinsic source of fire resistance is among the best forms of protection for a hero's inventory, and dwarvish cloaks can protect items from being burnt ⁹⁄₁₀ of the time, making them viable in a pinch. Players that are especially annoyed or inconvenienced by flaming spheres may opt to genocide them, including the use of a blessed scroll of genocide to eliminate other spheres alongside it (such as the much more destructive shocking sphere).

The flaming sphere's nonexistent MR score means they can easily be dropped by poison damage, and they can otherwise be immobilized by means such as a wand of sleep that gives the hero (and/or their pets) a chance to kill them before they explode. Cancellation that hits through their mediocre 4 AC will reliably disable their explosive abilities and render them harmless. Be sure to keep flaming spheres away from leprechaun halls, treasure zoos and similar rooms of monsters that you do not want awakened if possible, and if a zoo contains a flaming sphere, try to save it for last if possible—stealth can be a useful aid for both purposes, though it will not always prevent sleeping monsters from awakening.

History

The flaming sphere first appears in NetHack-- 3.0.10, and also appears in NetHack-- 3.1.3 and SLASH 6. It makes its vanilla debut in NetHack 3.3.0. From this version to NetHack 3.6.7, including some variants based on those versions, the difficulty of the flaming sphere is 8: its explosion attack targets a single square, has a dexterity-based chance of dealing reduced damage, does not burn armor or other items, and is completely blocked by fire resistance.

The flaming sphere's current behavior is introduced in NetHack 5.0.0 via commit 6b60618e and commit eb22a810, with the explosion behavior adapted from xNetHack, while its monster difficulty rating is increased to 9—NetHack 5.0.0 fixes discrepancies related to the difficulty ratings for spheres via commit c3802343.

Flaming spheres are also the subject of other software bug fixes and adjustments over several versions:

• In versions up to NetHack 3.4.2, flaming spheres are not properly accounted for in some checks that involve fiery monsters, and polymorphing into a flaming sphere does not cure sliming. These are fixed in NetHack 3.4.3 via commit 5ba58b72 and commit 929f9ce2 so that polymorph into a flaming sphere cures sliming and the monster is accounted for using a macro rather than separate lists.
• In versions up to NetHack 3.4.3, flaming and shocking spheres are capable of picking up items where a freezing sphere cannot, though due to their weight they will only attempt to pick up very light ones (such as singular gold pieces) and will usually only do so while tame. This is fixed in NetHack 3.6.0 via commit cbab68a4 so that all three spheres will properly avoid picking up items.
• In versions up to 3.6.7, flaming spheres grant fire resistance only while eaten, which does not account for any form of digestion attack. This is fixed in NetHack 5.0.0 via commit 0eadf8df, commit b25961fb and commit c78e7af0.

Variants

NetHack variants created prior to NetHack 5.0.0 may or may not retain the flaming sphere's behavior from previous versions.

SLASH'EM

In SLASH'EM, flaming spheres behave mostly as they do in NetHack 3.4.3 and previous contemporary versions. Flaming spheres and heroes polymorphed into flaming spheres take damage when subjected to water, such as from a rust trap or the thrown potion, and are similarly affected by the thrown or wielded potion of amnesia.

SLASH'EM makes the spellbook of flame sphere and its spell functional: casting the spell summons a tame flaming sphere with 1 HP, and casting it at Skilled or higher in matter spells can summon multiple spheres. These flaming spheres will only exist temporarily, 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, angering peaceful monsters and so on. The spell also respects extinction, meaning it has a finite number of uses throughout a given game.

All of the above information also applies to SlashTHEM.

dNetHack

In dNetHack, notdNetHack and notnotdNetHack, flaming spheres have an on-death explosion similar to gas spores, covering a 3x3 area centered on it that can burn items in the open inventories of anyone caught in the blast—fire resistance blocks HP damage from the explosion, and extrinsic fire resistance also prevents item damage.

Flaming spheres can be warded by the Elder Elemental Eye at any level of reinforcement.

Flaming spheres may 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 randomized to fire. The summon sphere monster spell can summon flaming spheres.

Similar to SLASH'EM, flaming spheres (including heroes polymorphed into flaming spheres) take damage when subjected to water, such as from the thrown potion, and are similarly affected by the potion of amnesia or potion of starlight if they are thrown or wielded.

SpliceHack

In SpliceHack, flaming spheres behave as they do in NetHack 3.6.7 and previous versions.

The spellbook of flame sphere is made functional and works similar to SLASH'EM.

Reading a scroll of elementalism while confused has a ¹⁄₄ chance of summoning flaming spheres, which are tame if the scroll was blessed and read by a hero and will otherwise be hostile.

All of the above information also applies to Hack'EM.

EvilHack

In EvilHack, flaming spheres use explosion attacks and on-death explosions that cover a 3x3 radius centered on its square, burning monsters, armor and items caught in the explosion—armor that is burnt enough can also be destroyed.

Two flaming spheres are generated in the lava-filled room on the ground floor of the Wizard's Tower during level creation.

Encyclopedia entry

See the encyclopedia entry for sphere.