Displacement

This article is about the property. For displacing pets by switching places, see Pet#Speed.

Displacement is a property in NetHack that causes your image to appear a tile or two away from where you actually are, which can misdirect the attacks of hostile monsters. The cloak of displacement is currently the only source of the property: no monsters have intrinsic displacement.

The following information pertains to an upcoming version (3.7.0). If this version is now released, please verify that it is still accurate, then update the page to incorporate this information.

Displacer beasts have the displacement property, and fighting them may cause you to displace them instead of attacking; force-fighting via F may similarly cause you to attack thin air. The corpse or tin of a displacer beast confers temporary intrinsic displacement when eaten.

Description

Displacement will make a particular given monster think you are at a random square within a 5×5 area centered on the player; in other words, the monster will think you are 0–2 squares away from where you are. If you do not have a clear line of sight to the monster, it will only generate the image in a 3×3 square around you; this is presumably to prevent monsters being alerted to your presence from well around corners, or from the other side of a closed door.

A monster that does not know your location has a ¹⁄₄ chance of figuring out where you actually are during each of its turns; a monster that knows your location is not affected by displacement, but you must be 'found' again each time you move similar to invisibility. A monster fooled by your displaced image will often attack it instead of you - the monster may even move in the wrong direction entirely, with the odds of this varying widely depending on your surroundings and movement. Shopkeepers and aligned priests are not fooled by displacement if you are generating conflict, and they will not hesitate to attack you.

Displacement is done per-monster, so your displaced image will generally be in two different locations for two different monsters. This makes it possible for one monster to see your image in the square of another monster - monster melee attacks that target such a square will miss, but breath weapons, ranged weapons and the like will still deal damage.

Bribery

If a lawful demon prince teleports to you to demand a bribe while you have displacement, they may warp next to your displaced image; this will cause them to become hostile without a chance of being pacified.

Strategy

Displacement or invisibility is invaluable when running from a fight you are ill-equipped for, especially in the early game. Non-elven Rangers notably start with a +2 cloak of displacement - elven rangers are given an elven cloak instead to counterbalance their better weapons.

Invisibility is a property that can be similarly powerful in the early game - it applies a −2 to-hit penalty to monsters that cannot see you, and invisibility tends to be far more common and accessible than displacement. Even if you are discovered, moving will usually cause them to attack the square you previously occupied; however, the odds of discovery are more likely, with a ¹⁄₃ chance during each of their turns compared to ¹⁄₄ for displacement. Since both properties function on a per-monster-turn basis, fast monsters such as soldier ants are likely to find you quickly no matter which of them you use - invisibility will also override displacement if you have both properties, unless you are fighting monsters that can see invisible.

In the long term, monsters that can see invisible become more common as you progress; fewer monsters are unaffected by displacement, and even demon lords and princes can be fooled by it, though beware of this if you intend to bribe the lawful ones!

Variants

Some variants implement a form of monster displacement: among those, a few also grant it to two deferred monsters within the code - the shimmering dragon, whose scales are intended to confirm displacement, and its baby form.

SLASH'EM

In SLASH'EM, monster displacement exists: only displacer beasts have the property intrinsically. Shimmering dragons and their babies instead have a much lower AC than other dragons, simulating "displacement" by making them harder to hit.

GruntHack

GruntHack implements proper displacement for monsters. Monsters can appear in a different location from where they actually are, including inside walls, or on another monster's location. Monster displacement will only fool the player character's vision - telepathy or monster detection will reveal their actual location, making it possible for the displaced monster to show up on two different squares. Trying to walk onto a displaced monster's square will not attack it.

Adult shimmering dragons have intrinsic displacement, and their scales confer displacement.

FIQHack

FIQHack implements monster displacement that is somewhat similar to GruntHack, with the following differences:

• If you can sense the monster with telepathy, monster detection or similar, the displaced image will never be shown. If you can't see the displaced image, but would be able to see the true location, you will see the monster's true location.
• The displaced image will never appear in a spot the monster couldn't normally be on, such as inside walls.
• You will (try to) attack displaced images if moving onto them. If there is another monster there, you will attack it. The same thing now happens if a monster tries to attack your (or another monster's) displaced image that is on another monster.
• Unlike in GruntHack, baby shimmering dragons also have intrinsic displacement.

xNetHack

In xNetHack, eating a displacer beast corpse will confer intrinsic displacement for a short time.