# Potion of object detection

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Name

object detection

Appearance

random

Base price

150 zm

Weight

20

Monster use

Will not be used by monsters.

The potion of object detection is a potion that appears in NetHack.

Contents

1 Generation
2 Description
3 Strategy
4 Messages
5 References

Generation
Nymphs have a 50% chance of being generated with a potion of object detection.[1][2]
A potion of object detection is always present in The Gnome King's Wine Cellar variant of Mines' End.

Description
When quaffed, the potion of object detection will show you the location of all objects on the current level, with specific information dependent on beatitude. You also exercise wisdom if at least one object is detected this way.

Case

Effect

uncursed

You exercise your wisdom.
You "detect objects": every item sitting on the ground on your level is drawn on your screen. This tells you the type of every item but it does NOT tell you exactly what each item is. In other words: the potion tells you "There's a scroll here!" but it does NOT tell you "The scroll is VELOX NEB!" or "The scroll is enchant armor!" The glyphs are colored, so you can distinguish between some items by color, even without being explicitly told their appearance.
Items carried by monsters are also detected, but you will only see one item per monster.
E.g., if you see a "?" on your screen after quaffing an uncursed potion, it is either a scroll lying on the ground or one being carried by a monster, but you don't know what kind of scroll it is.

blessed

You exercise your wisdom.
You learn the appearance of every item on the ground on your level, except those in the inventories of monsters. While an uncursed potion will only tell you "There's a scroll here!" a blessed potion will tell you "The scroll is VELOX NEB!" or "The scroll is enchant armor!". In other words, you get exactly as much information as you would get if you had stood on the same square as the object without being blind.
You also learn the appearance of every item in your inventory, which is significant if you are blind.
You do NOT learn the appearance of the items carried by monsters, but you do detect those items just as you would with an uncursed potion.
E.g., if you see a "?" on your screen after quaffing a blessed potion, and farlooking the object produces "? a scroll (scroll)" then you know that that is a scroll that is being carried by a monster. If farlooking the object produces the message "? a scroll (scroll labeled VELOX NEB)" then you know that that scroll is lying on the ground.

cursed

You exercise your wisdom.
Works just like an uncursed potion, except that mimics are detected too, and drawn on screen as if they were items (the class of item is selected randomly).
e.g., if you see a "?" on your screen after quaffing a cursed potion it MAY be a scroll lying on the ground, or one being carried by a monster, but it could also be a mimic.

Treasures detected in the walls are always real - if the symbol suddenly disappears as you move adjacent to a marked spot, it means that the items are buried in the floor, and you can dig a pit by applying a pick-axe down to retrieve them. Items sitting on or embedded in the same tile may obscure further buried treasure.
Note that because tiles ports show unique tiles for unique object descriptions, you can determine the appearance of an object in tiles mode using an uncursed potion; once you've detected it, compare the tile to a list to see what appearance it has.

Strategy
Potions of object detection can be used to remotely detect the exact location of vaults, which will display as a 2x2 square of gold symbols unless the vault was looted, e.g. by a digging dwarf or a rock mole. They are also sometimes saved for the Castle as an easy way to detect where the chest containing the wand of wishing is.
Potions of object detection can also be very useful when combined with magic mapping in Gehennom - a player can quickly pass through Gehennom after locating all the staircases and prioritize which loot they want without having to walk through the mazes. Be on the lookout for detected wands, as they may signify a wand of digging carried by a minotaur.
As they are fairly common due to nymphs being generated with them, potions of object detection can be saved up and diluted en masse for holy (or unholy) water production.

Messages
You have a strange feeling for a moment, then it passes.
No objects on the level.You are a beginner and not hallucinating.
You have a normal feeling for a moment, then it passes.
No objects on the level.You are a beginner and hallucinating.
You feel a lack of something.
There were remembered, now gone, objects.
You sense objects nearby.
The only objects detected are on your square.You are not hallucinating.
You sense something nearby.
The only objects detected are on your square.You are hallucinating.
You sense the presence of objects.
Objects detected.You are not hallucinating.
You sense the presence of something.
Objects detected.You are hallucinating.
You sense the absence of objects.
No objects detected.There were no remembered objects.
References

↑ makemon.c in NetHack 3.4.3, line 586

↑ makemon.c in NetHack 3.4.3, line 636

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