Yellow light

From NetHackWiki
Jump to navigation Jump to search

A yellow light, y, is a type of monster that appears in NetHack. As an amorphous monster made of energy, it can flow under doors.

Its sole means of attacking is to explode towards its target - this destroys itself, blinds the target for 10d20 turns, and wakes nearby sleeping monsters. The attack is much less effective if you cannot see the yellow light - if it is invisible and you do not see invisible, there is a chance based on your level that it will not affect you.[1]


In addition to normal random generation, if yellow lights are not genocided, reading a noncursed scroll of light while confused has a 15 of summoning a yellow light instead of the standard confused effect.

The second variant of Medusa's Island has a yellow light in the back room of the hall Medusa inhabits, and three yellow lights are generated on the Plane of Air.

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.

Reading a noncursed scroll of light while confused will instead summon multiple tame cancelled yellow lights if they are not genocided. An uncursed scroll will summon 3–4 y yellow lights, while a blessed scroll will summon 5–6 yellow lights.


Blinding yourself, e.g. by wearing a blindfold or towel, will render the explosion harmless; a unicorn horn or curative spell (e.g., extra healing and cure blindness) also make this trivial to deal with. Yellow lights also cannot see invisible - if you are invisible or displaced, they may explode at an empty square with no effect.

While it is possible to kill yellow lights normally if you can deal with their 0 AC and fast, erratic movement, it is usually preferable to let them explode while already blinded with the exception of specific scenarios. On that note, be careful of dealing with yellow lights in or around rooms such as treasure zoos or throne rooms - a light that explodes close to the room will wake many (if not all) of the inhabitants.


Yellow lights have been present in the game since Hack121, a variant of Jay Fenlason's Hack.


You get the impression it was not terribly bright.
An invisible yellow light exploded, and you were unaffected by it.
You have a melancholy feeling for a moment, then it passes.
A tame yellow light exploded.



In UnNetHack, yellow lights are subject to special generation on the Oracle level, where only 93% of monsters are generated through normal means; of the remaining 7%, yellow lights have a 110 chance of being generated.

Encyclopedia entry

Strange creatures formed from energy rather than matter,
lights are given to self-destructive behavior when battling