Yellow light

y yellow light
Difficulty	5
Attacks	Explode blind

y yellow light
Difficulty	5
Attacks	Explode blind
Base level	3
Base experience	43
Speed	15
Base AC	0
Base MR	0
Alignment	0 (neutral)
Frequency (by normal means)	Common
Genocidable	Yes
Weight	0
Nutritional value	0
Size	Small
Resistances	Fire, Cold, Shock, Disintegration, Sleep, Poison, Acid, Stoning
Resistances conveyed	None
A yellow light: can fly. can flow under doors. does not breathe. cannot pick up items. has no eyes. has no limbs. has no head. is mindless. does not have a solid form. does not eat. (*) is neither male nor female. is normally generated hostile. can be seen through infravision. never leaves a corpse.
Reference	monst.c#line1037

A yellow light will explode (permanently destroying the light) and blind you when adjacent, but cause no other damage. The blindness will last for 10d20 turns.

As yellow lights can't see invisible, if you are invisible or displaced they may explode at an empty square with no blinding effect.

The explosion of a yellow light will wake nearby sleeping monsters.

Strategy

The best course of action is to put on a blindfold or towel and wait for it to explode, or to have a blindness cure ready. If it is invisible then it wont blind you and you get the message "Something explodes, but you get the feeling it wasn't too bright".

Encyclopedia entry

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