You searched for NIGHTVEIL
1. nightveil
Syntax: cast nightveil (<object>)
Casting nightveil on an object which is glowing will snuff out the light
surrounding the object, removing the glow flag. If an item doesn't have the
glow flag, it will give it the dark flag.
Casting nightveil on a room will cause it to become shrouded in darkness.
Players or mobiles entering the room will not be able to see the
surroundings without the darkvision spell if there are no lights in the
room. Some areas (such as recall) do not allow this spell to be cast in
its rooms.