# Spellbook of fireball

spellbook of  +   fireball   

Appearance

random

Abundance

2.03%

Base price

400 zm

Weight

50

Turns to read

12

Ink to write

20–39

Spell type

attack

Level

4

Power cost

20 Pw

Direction

ray/distant

A spellbook of fireball allows you to learn the spell of fireball.

Contents

1 Effects

1.1 Unskilled or basic
1.2 Skilled or expert

2 Strategy
3 History
4 Messages
5 References
6 See also

Effects
The spellbook of fireball is fireproof, preventing it from being destroyed by other sources of fire damage (e.g. a scroll of fire or a fire trap).
The spell of fireball is a medium-level attack spell that has different effects depending on the character's skill level in attack spells; both spells will produce an explosion of fire. Being caught in an explosion will cure sliming.
Ice in the affected squares melt into pools of water, while pools and fountains evaporate and dry up; pools will leave pits behind, while moats will not be affected. Closed doors will be destroyed, but other objects such as boulders are unaffected. Scrolls, books and potions in the explosion's area may be destroyed, while cloth and leather items may be burnt—this includes items in affected monsters' inventories, though scrolls of fire and the Book of the Dead will resist in addition to the spellbook of fireball itself. Exploding potions will subject nearby monsters to their vapors.

Unskilled or basic
Casting the spell at Basic skill or lower creates a ray of fire; NetHack will prompt you for a direction in which to cast the spell. When the ray hits an obstacle or monster, it explodes, affecting the hit square and all 8 adjacent squares. Monsters caught in the explosion are hit for 12d6; monsters with cold resistance take double damage, while targets with monster MR may resist for half the damage. 

Skilled or expert
When casting the spell at Skilled or higher, you may choose a location to target the spell with. The following must apply for a tile to be eligible:

The location is no more than 10 squares away.
The square must be an open space.
You must be able to see the chosen square normally (i.e. it must be lit and in line of sight).
If you are engulfed, the explosions will be centered around yourself, and nothing will be affected outside the engulfing monster.[1][2] If you are on the Plane of Water, you are prevented from casting the spell outright.[3]
Two to nine explosions will follow—if there is a wall on the straight line between you and your target, the spell will explode around the square immediately before the first wall;[4] otherwise, the explosions will be centered around the location you chose. The first explosion is centered on the selected location, and the subsequent ones will occur randomly on that square or any of the eight squares around it; the explosions themselves each affect a 3×3 square area around their center.[5]
The effects of a Skillred or higher fireball are equivalent to a Skilled or higher cone of cold. That is, the damage to non-cold-resistant monsters is just XL/2 + 1 plus spell damage bonus, halved if they resist, doubled if they are resistant to cold, and doubled again is they're grabbing you and you're within blast radius. Monsters are dealt additional damage equal to the number of items destroyed in their inventory, even if they're fire resistant.

Strategy
It is worth planning out how to allot your skill slots ahead of time if you plan to make extensive use of this spell. Advancing from Basic to Skilled in attack spells deprives you of the ability to explode fireballs in dark squares, but otherwise massively increases the destructive power of the spell; enhancing to Expert skill gives no benefits beyond lowered failure rate. At Skilled or higher, the minimum safe range to avoid being caught in the explosion is 3 squares away; this can still kill monsters standing next to you if the random explosions are positioned favorably.
Though a lamp can work to increase vision in dark areas, the wand or spell of light is a more useful supplement, as it can permanently illuminate a much larger area, allowing you to cast at more distant targets. You may generally want to avoid targeting squares near fountains if you plan on using them later, e.g. hunting for wishes.
Players who are concerned about destroying valuable items along with their foe will want to consider a less destructive alternative. Magic missile does not affect the inventory in any way, and the cone of cold will only destroy potions—the "best" spell of the three depends entirely on the situation at hand. Magic missiles and Basic-skill-or-lower cones of cold can also bounce to inflict extra damage via rebounds, and their base damage scales with your level, eventually surpassing fireball at higher levels; conversely, fireballs will always do a set amount of damage and cannot bounce, but also cannot miss and may inflict extra damage from destroying potions and armor. This also makes fireball a more preferable spell in more open areas with fewer or no walls, such as Medusa's Island.

History
Prior to NetHack 3.6.1, the skilled and expert version of the spell can target any monster within ten squares as long as the player can sense it, e.g. via telepathy, infravision, or a blessed potion of monster detection; warning will not suffice, as it only shows where a monster is located.[6]

Messages

<monster> is caught in the fireball!
You cast the spell and hit a monster.
You are caught in the fireball!
You cast the spell and hit yourself, or else cast it while engulfed.
Steam billows from the fountain.
A fountain was evaporated by the spell.
The water evaporates.
A pool of water was evaporated by the spell.
Some water evaporates
A moat was in the range of the spell's explosions.
You hear hissing gas.
As above, but the source of water was out of sight.
The door is consumed in flames!
A closed door was caught in an explosion.
You smell smoke.
As above, but the door was out of sight.
You see a puff of smoke.
You destroyed a book or scroll.
You smell a whiff of smoke.
As above, but the book or scroll was out of sight.
Your mind fails to lock onto that location!
You tried to cast the spell at a location out of sight.
The spell dissipates over the distance!
You tried to cast the spell over too great a distance.
You're joking! In this weather?
You tried to cast the spell while underwater.
You had better wait for the sun to come out.
You tried to cast the spell at Skilled or higher on the Plane of Water.
References

↑ spell.c in NetHack 3.6.1, line 1241

↑ explode.c in NetHack 3.6.1, line 88

↑ spell.c in NetHack 3.4.3, line 975

↑ dothrow.c in NetHack 3.6.1, line 442

↑ spell.c in NetHack 3.6.1, line 1048

↑ spell.c in NetHack 3.6.1, line 1232

See also
Wand of fire
Fire horn
Spellbook of cone of cold

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