Light (monster class)
The light is a monster class that appears in NetHack, and is represented by the lowercase y glyph (y). Lights are designated internally by the macro S_LIGHT.[1]
The class contains two monsters:[2]
Common traits
Lights are neutral monsters that are amorphous, mindless and unsolid. They are unbreathing and capable of flight, and they are immune to the blinding effects of flashes from expensive cameras (though a sleeping light will still be awakened).[3] Lights have a somewhat-low 0 AC and no MR score.
A light's only form of offense is an explosion attack directed at the target's square: this destroys the light, causes a status affliction if it hits the hero or a monster (blindness for yellow lights and confusion for black lights), and also creates noise that can wake nearby sleeping monsters. Lights possess every resistance property other than magic resistance.
Body parts
Lights have a special hard-coded set of body parts, with "hand" replaced with "ray", "handed" replaced with "rayed", and all other body parts replaced with "beam".[4]
Generation
Randomly-generated lights are always created hostile.
Reading a scroll of light while confused has a 1⁄5 chance of summoning a light monster if they are not extinct or subjected to genocide.[5][6]
Lights do not leave corpses upon death.
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 1ba1422e, reading a scroll of light while confused summons multiple tame and cancelled lights. An uncursed scroll will summon 3–4 yellow lights, a blessed scroll will summon 5–6 yellow lights, and a cursed scroll will summon 3–4 black lights.History
The yellow light first appears in Hack 1.21 and Hack for PDP-11, which are both based on Jay Fenlason's Hack, and is part of the initial bestiary for Hack 1.0. The black light first appears in NetHack 3.2.0.
Variants
Many NetHack variants add new monsters to the light monster class, with some implementing the will o' wisp from the biodiversity patch—in the original patch, they can explode and render a target confused for several turns, and their exact traits across variants will vary.
UnNetHack
In UnNetHack, reading a scroll of light while confused summons multiple tame and cancelled lights. An uncursed scroll will summon 3–4 yellow lights, a blessed scroll will summon 5–6 yellow lights, and a cursed scroll will summon 3–4 black lights.
dNetHack
dNetHack, notdNetHack and notnotdNetHack add three monsters to the monster class:
Coure Eladrin turn into motes of light to flee and recover at low health, while Queen Mab turns into a coterie of motes for similar purposes. The tiny being of light is one of the many insight merchants.
SpliceHack
SpliceHack and its rewrite both add the will o' wisp, but implement it differently from the biodiversity patch.
SlashTHEM
SlashTHEM incorporates the will o' wisp, with most of the same traits as in the biodiversity patch.
