Invisibility

Invisibility is a property in NetHack that prevents a hero or monster who is invisible from being seen by most other monsters.

Description

Invisibility functions somewhat differently for the hero than it does for monsters. A hero or monster with the see invisible property can see invisible beings, including themselves if they are invisible.

For the hero, invisibility grants the following qualities:

• An invisible hero cannot be seen on the map, though their position may still be highlighted by the terminal cursor depending on the operating system and/or terminal program.
• Hostile monsters that cannot see invisible will have difficulty locating the hero—when attacking, they will incur a -2 to-hit penalty and target whichever square they believe the hero to occupy.
  • Hostile monsters have a ¹⁄₃ chance of discovering an invisible hero's location each turn if the hero remains in place.
  • Displacement will not affect a monster that cannot see an invisible hero with the property.
  • An invisible hero applying a mirror at a monster has no effect on that monster if they cannot see the invisible hero.
  • The stoning gaze of Medusa cannot be reflected by an invisible hero using a mirror or a source of reflection.
• Though shopkeepers cannot see invisible, they will sense an invisible hero's presence and move towards the doorway to prevent them from walking into or out of their shop through the doorway. An invisible hero that manages to enter or leave the shop, e.g. through means such as teleportation or phasing, will not anger the shopkeeper (provided the hero does not steal anything) and can shop as normal.

For a monster, invisibility grants the following qualities:

• An invisible monster's glyph cannot normally be seen on the map—extrinsic telepathy and see invisible can render them visible to the hero, while warning will highlight an invisible monster's position with a numbered glyph if their level is high enough.
• Bumping into an invisible monster or being attacked by one will mark their square with a I. Bumping into a peaceful invisible monster will anger them.
• Searching will mark the location of unseen monsters, including invisible ones, with I as above, though they will often move from that location on their turn.

Stalkers and black lights are monsters that are always generated invisible.

A worn mummy wrapping suppresses the hero's invisibility until it expires or the wrapping is removed, and can also block the application of invisibility from certain sources. Monsters wearing mummy wrappings will also be made visible if they are already invisible, and the wrapping will suppress any invisibility applied to those monsters by items while it is worn.

Intrinsic theft attacks from gremlins can remove a hero's invisibility.

Sources

There are multiple methods of becoming invisible, which also differ for the hero and for monsters. As noted where appropriate, a tame or peaceful monster will only make themselves invisible using the listed methods if the hero currently has the see invisible property.

• Quaffing a potion of invisibility grants invisibility:
  • For the hero, quaffing the potion grants permanent invisibility for the hero if it is blessed, and otherwise grants the property for 31-45 more turns—quaffing a cursed potion will also aggravate all monsters on the level, which awakens all sleeping and meditating monsters and has a ¹⁄₅ chance of restoring mobility to immobile monsters.
  • A monster that is not invisible and quaffs a potion of invisibility will become permanently invisible regardless of beatitude—a monster quaffing a cursed potion will also highlight their position at the time of quaffing and "aggravate" the hero, awakening them if they are unconscious. Monsters will not seek out or quaff the potion if they have a gaze attack and are not cancelled, they are wearing a mummy wrapping, or else if they are not hostile and the hero lacks see invisible.
• Zapping a wand of make invisible grants invisibility:
  • A hero that zaps the wand at themselves becomes permanently invisible unless they are wearing a mummy wrapping.
  • A monster that is zapped with the wand by a hero or else zaps it at themselves gains permanent invisibility. Monsters will not seek out or quaff the potion if they have a gaze attack and are not cancelled, they are wearing a mummy wrapping, or else if they are not hostile and the hero lacks see invisible.
  • A hero that breaks the wand by applying it releases a damaging magical blast that has a ¹⁄₁₀ chance of giving the hero permanent invisibility, and otherwise makes them invisible for up to 250 more turns, with a worn mummy wrapping nullifying the invisibility in either case.
• The invisibility spell grants the property to a hero that casts it for 31-45 more turns unless they are wearing a mummy wrapping, similar to quaffing the uncursed potion.
• A hero or monster that wears a cloak of invisibility will become invisible while the item is worn.
• A hero that puts on a ring of invisibility gains invisibility, and a hero eating the ring has a ¹⁄₃ chance of absorbing its magic and granting permanent invisibility. Monsters will not wear the ring.
• Eating the corpse or tin of a stalker will stun the hero for several turns and apply invisibility based on their current state—a hero that is not invisible (including one wearing a mummy wrapping) will become invisible for 50-149 turns, while a hero that is already invisible will become permanently invisible and gain the see invisible intrinsic. Monsters cannot gain invisibility from eating stalkers.
• Polymorphing into a stalker or black light will render a hero or monster invisible while they are in that form.
• The disappear monster spell can be cast be any monster that can cast mage spells and has a monster level of at least 5, and grants the caster permanent invisibility. Monsters will only cast the spell if they are not yet invisible, and monsters that are not hostile will not cast this spell if the hero cannot see invisible.
• Invoking The Orb of Detection toggles a hero's invisibility on or off.

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

Per commit f83a57c5, the following changes are implemented for some invisibility sources:

• A hero quaffing a blessed potion has a ¹⁄₃₀ chance of becoming permanently invisible, which is reduced to ¹⁄₁₅ if they are currently invisible when quaffing the potion. Otherwise, the hero gains (3d100)+100 (more) turns of temporary invisibility.
• A hero quaffing an uncursed potion becomes invisible for (6d100)+100 (more) turns, which also applies to a hero casting the invisibility spell if they are not wearing a mummy wrapping.
• A hero quaffing a cursed potion becomes invisible for (9d100)+100 (more) turns, and all sleeping and meditating monsters on the level are awakened as before.
• A hero zapping the wand of make invisible at themselves gains 31–45 more turns of temporary invisibility, rather than permanent invisibility.

Per commit 9bd8fcf8, a hero quaffing the cursed potion has their intrinsic invisibility removed before the temporary invisibility is applied.

Per commit 2bd43869, stepping on a magic trap can toggle permanent invisibility on or off as one of its many effects, which is adapted from SporkHack.

Per commit 8d2407f1 and commit 0eadf8df, monsters can gain intrinsics from eating corpses and engulfing monsters, causing them to turn invisible if they eat a stalker corpse or swallow one whole.

Strategy

Invisibility has a number of perks, especially for crafty players. Pets gain no benefits from being invisible, as it does not affect monster-versus-monster combat and heroes that lack see invisible will have a harder time keeping track of them.

As tame and peaceful monsters that have a way to turn invisible will only do so if you have see invisible, this is particularly dangerous if you got the property from drinking a non-blessed potion of see invisible: you will not be able to see the monster once the property expires, and bumping into invisible monsters other than pets will anger them, which is potentially fatal if you do so with the watch or a shopkeeper.

Fighting while invisible

Invisibility is a good evasive aid, usually resulting in hostile attackers missing more often unless you stay in one place: it is especially useful in the early game, where few monsters will have see invisible, and can aid in escape from unexpectedly powerful foes. This can also double as an offensive aid that helps you keep targets off-balance while picking them off from a distance, e.g., with projectiles or polearms. As the game progresses, you will encounter more monsters with see invisible, limiting its effectiveness (unless paired with something like displacement).

Since the passive gaze of a floating eye relies on you seeing it, an invisible hero can still be paralyzed by it—however, turning the eye invisible instead will render the gaze ineffective if you cannot see invisible, making the eye harmless and allowing you to attack it with impunity. Invisible floating eyes will also not paralyze pets that cannot see invisible, which is especially useful for pacifists.

Invisibility can actually be a disadvantage in certain scenarios: unicorns in particular cannot see invisible and will not know the player's location to keep a knight's jump away, meaning that hostile unicorns will close in unexpectedly and likely skewer an early character. Conversely, invisible players can safely approach co-aligned unicorns to throw their gems at, and cross-aligned ones will be easier to kill or pacify for a prepared character. Invisibility can also make controlling other monsters for various purposes difficult if they lack see invisible, e.g., luring soldiers into trap doors in the Castle or pulling wraiths away from non-graveyard levels.

The mummy wrapping is a good cloak for players who elects to remain invisible long-term, but find it necessary to become temporarily visible for certain tasks. Like any other piece of armor, be sure to verify the beatitude of a wrapping before trying it on. If you temporarily remove another cloak to use a wrapping, make sure to replace the cloak once you're done.

Fighting invisible monsters

Invisible monsters can be annoying to deal with, and are especially aggravating if the monster is already decently strong on its own: shapeshifters that turn into powerful-enough spellcasting monsters can cast disappear, and will retain their invisibility even after they shift forms again. Searching can reveal their approximate location and help you take the fight to them, and you can also lure the monster down a narrow hallway to make it easier to target—monsters that drink cursed potions of invisibility will also "aggravate" you, revealing their location to you temporarily and allowing you to plan accordingly.

Pets are not deterred by invisibility and can pick an invisible monster off as it approaches, though a black light that a pet attacks will likely explode and confuse them. Humanoid pets should be given a unicorn horn as soon as possible to prevent them attacking you in turn, while some other pets can be kept occupied or at bay with treats in order to get some space until the confusion wears off. You can also potentially identify some items depending on whether or not you find them on an invisible monster: for example, monsters can generate with a wand of make invisible as a miscellaneous item—if you recently heard a zap prior to encountering and killing an invisible monster that drops a wand, and that wand makes engravings vanish, it is likely (but not always) a wand of make invisible.

Invisibility and shops

One of the main disadvantages to invisibility is the hassle of shopping, since you must make yourself visible to enter and invisibility from a blessed potion, a cursed ring or cursed armor can be difficult to deal with. Most players should keep a mummy wrapping or two on hand in case they accidentally wear such a cursed item and cannot remove it, obtain invisibility that cannot be toggled, or else simply plan to shop while invisible—watch out ofr cursed cloaks of invisibility in particular, which will prevent the use of mummy wrapping.

History

Invisibility has been present in the game since Hack 1.21, which is based on Jay Fenlason's Hack.

Messages

Gee! All of a sudden, you can't see yourself.

You quaffed a potion of invisibility.

Gee! All of a sudden, you can see right through yourself.

As above, but you have see invisible.

Far out, man! You can't see yourself.

You quaffed a potion of invisibility while hallucinating.

Far out, man! You can see right through yourself.

As above, but you also have see invisible.

Suddenly you cannot see <the monster>.

A monster became invisible by quaffing a potion of invisibility.

<The monster's> body takes on a <strange/normal> transparency.

As above, but you have see invisible, with "normal" used if you are also hallucinating.

You are invisible <to others>.

You are invisible as viewed via enlightenment, with "to others" added if you can see invisible.

You are visible.

As above, but you are wearing a mummy wrapping.

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

Per commit 2bd43869 above, the following messages are added.

You can see yourself again!

You lost intrinsic invisibility.

You can't see through yourself anymore!

You lost intrinsic invisibility while having the see invisible intrinsic.

You feel a little more obvious now.

You lost intrinsic invisibility, but have extrinsic invisibility.

You feel a little more hidden now.

You gained intrinsic invisibility while you have extrinsic invisibility.

Variants

NetHack variants add new sources of invisibility and may give certain monsters like ghosts the ability to become invisible temporarily, as well as altering the mechanics of the property or its sources. Some variants also make is possible for items to be invisible as well, which may affect the functions of those items as well—this and more are explored in detail within the article linked above.

SLASH'EM

In SLASH'EM, items can be generated very rarely as being invisible, and invisible monsters that are killed will leave invisible corpses—the wand of make invisible and potion of invisibility can also be used to make items invisible.

The vanish technique causes the hero to become invisible and very fast temporarily, and is available to all gnomish heroes.

Invoking the Gauntlets of Defense can toggle the hero's invisibility on or off.

Pixies and star vampires are always generated as invisible, though only the latter are defined as always-invisible monsters. Lawful demon princes that demand a bribe from the hero–Asmodeus, Baalzebub, Dispater, and Geryon–will always be generated as invisible.

If the 7 of trumps representing the Hermit is drawn from a gypsy telling the hero's fortune, the hero will gain invisibility for 500–1000 turns along with teleportitis for 300–600 turns.

GruntHack

In GruntHack, invisible items function similarly to SLASH'EM, being created very rarely by normal object generation—a critical difference from SLASH'EM is that sources of invisibility are highly likely to generate as being invisible themselves.

SporkHack

In SporkHack, magic traps can toggle permanent invisibility on or off as one of their many effects.

Boojums have a claw attack that deals no damage, but teleports the victim and temporarily turns them invisible.

dNetHack

In dNetHack, some of the monsters introduced in the variant can generate as invisible, or may even become invisible under special circumstances:

• The Grue is invisible while it inhabits an unlit square, and invidiaks demonstrate similar behavior.
• Hellcats can become invisible in lit squares, and invisible ones will become visible in unlit squares.
• Star vampires are normally always invisible, but will become visible for a short time after draining a hero or monster's blood—a hero must have at least 10 insight to perceive star vampires at all.
• Lawful devil lords and princes that will attempt to bribe the hero are always generated as invisible.
• Center of All and the Aspects of The Silence are always generated as invisible.
• Phantom fungi, id juggernauts, perfectly clear cubes, darkness given hunger, and ancients of death are always invisible.
• Phantasms have a roughly ¹⁄₂ chance of generating as permanently invisible.
• Hudor Kamerel created in pool squares are always invisible.

An invisible hero or monster wearing shadowsteel armor has a much lower chance of the armor eroding while they are in a lit square—fixed shadowsteel armor will gradually repair erosion if the wearer is not invisible and is in an unlit square.

Imperial elven body armor can grant invisibility while worn if its active camouflage system is repaired using a cloak of invisibility, ring of invisibility or wand of make invisible.

Prayer-warded wrappings can suppress invisibility while worn as mummy wrappings do.

The spirit Shiro grants invisibility while bound, and a hero attempting to wear a mummy wrapping or prayer-warded wrapping will have the action interrupted and unbind Shiro, usually destroying the wrapping in the process (unless it is an artifact).

Some artifacts in dNetHack can grant invisibility:

• Invoking Carnwennan, The Lifehunt Scythe, Hellrider's Saddle, or Whisperfeet toggles the hero's invisibility on or off.
• The Robe of Closed Eyes grants invisibility along with gaze resistance while worn.

FIQHack

In FIQHack, invisibility is one of the intrinsic properties a non-cursed potion of wonder can grant when quaffed, and dipping an appropriate item in a non-cursed potion also has a chance of giving it invisibility as an object property.

xNetHack

In xNetHack, invisibility functions as it does in NetHack 3.7.0.

¹⁄₄ of quasits are generated as invisible.

Ghosts can turn invisible and reappear to try and frighten the hero, which scares them into becoming immobile for 3 turns unless the hero can see invisible or otherwise sense the invisible ghost.

SpliceHack

In SpliceHack, invoking Carnwennan can toggle the hero's invisibility on or off.

notdNetHack

In notdNethack and notnotdNethack, in addition to dNetHack details, The Stone Mask is an artifact associated with Shiro that grants invisibility while worn.

EvilHack

In EvilHack, invisibility from existing sources functions much differently, and other sources and removal methods are added:

• Invisibility that is gained from a blessed potion of invisibility or a wand of make invisible is fairly long-lasting but not permanent.
• Zapping a cursed wand of make invisible will make invisible monsters visible, and a hero zapping one at themselves also has a ¹⁄₂ chance of aggravating all monsters on the current level—it has no effect on already-visible monsters.
• Magic traps can toggle permanent invisibility on or off as one of their many effects, similar to SporkHack.
• The lustrous ring grants invisibility while worn—The One Ring is an artifact lustrous ring that also grants additional benefits.

Similar to xNetHack, ghosts can turn invisible and reappear to try and frighten the hero, scaring them into freezing for 3 turns unless the hero can see invisible or otherwise sense the ghost.

As in SporkHack, boojums have a claw attack that deals no damage, but teleports the victim and temporarily turns them invisible.

SlashTHEM

In SlashTHEM, in addition to SLASH'EM details, invoking Nightingale or Shadowblade can toggle the hero's invisibility on or off.

SlashTHEM also adds the boojum, which behaves largely as it does in SporkHack.