Invisibility

Invisibility is a property in NetHack that prevents a hero or monster from being seen by any other monster without the the see invisible property.

Description

Invisibility functions somewhat differently for the hero than it does for monsters.

For the hero:

• An invisible hero cannot be seen on the map, though their position is still highlighted by the terminal cursor.
• 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 hostile monster that cannot see an invisible hero with the property.
  • Applying a mirror at a monster while invisible has no effect on them if they cannot see invisible.
  • The stoning gaze of Medusa cannot be reflected by an invisible hero with a mirror or a source of reflection.
• Shopkeepers cannot see invisible, but will prevent an invisible hero from entering or leaving their shop through the doorway. They will not become angry if an invisible hero manages to enter or leave the shop through means such as teleportation or phasing, provided the hero does not steal anything.
• 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.

For monsters:

• 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.

Sources

There are multiple methods of becoming invisible, which also differ for the hero and other monsters:

• Quaffing a potion of invisibility grants permanent invisibility for the hero if it is blessed, and otherwise grants the property for 31-45 more turns—a cursed potion will also aggravate all monsters on the level. A monster that quaffs a potion of invisibility of any beatitude will always become permanently invisible, though the cursed potion will also highlight the monster's position at the time of quaffing.
• Zapping a wand of make invisible grants permanent invisibility to a hero that zaps it at themselves unless they are wearing a mummy wrapping, and also grants permanent invisibility to a monster that zaps it at themselves.
• Applying a charged wand of invisibility to break it has a ¹⁄₁₀ chance of making the hero permanently invisible, and otherwise grants the property for up to 250 more turns.
• The invisibility spell grants the property to a hero that casts it for 31-45 more turns unless they are wearing a mummy wrapping.
• The cloak of invisibility grants the property while worn.
• The ring of invisibility grants the property while worn, and eating the ring has a ¹⁄₃ chance of absorbing its magic and granting permanent invisibility.
• Invoking The Orb of Detection toggles invisibility on or off for a hero that does not already have the property.
• Stalkers and black lights are always generated invisible.
• Eating the corpse or tin of a stalker will stun the hero for 50-149 more turns and grant the property for the same duration; if the hero is already invisible, doing so will grant permanent invisibility instead along with the see invisible intrinsic. Monsters cannot gain invisibility from eating stalkers.
• 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.

Of note is that a tame or peaceful monster will only make themselves invisible if the hero currently has the see invisible property.

The following information pertains to an upcoming version (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.

The wand of make invisible no longer grants permanent invisibility.

Strategy

Invisibility has a number of perks for especially crafty players. Pets gain no benefits from being invisible, as it does not affect monster-versus-monster combat, and will only make them harder to keep track of.

Tame and peaceful monsters that have a way to turn invisible, including spellcasters, 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, as you will not be able to see them once it expires. Bumping into invisible monsters will anger them - this is potentially fatal in the case of the watch and shopkeepers.

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 its passive gaze relies on you seeing it, a floating eye is not affected by a player's invisibility; however, turning the eye invisible instead will render the gaze ineffective (unless you have see invisible), rendering it harmless and allowing you to attack it with impunity. Invisible floating eyes will also not paralyze pets that cannot see invisible; this 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 Castle trap doors or luring 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 base monster was already decently strong (e.g., a stalker). 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 a monster off as it approaches; if the monster is a black light, however, it will likely explode and confuse them, causing them to potentially attack you in turn. Shapeshifters that turn into powerful enough spellcasting monsters can cast disappear, and will retain their invisibility even after they shift forms again.

Monsters can generate with a wand of make invisible as a miscellaneous item; if you recently heard a zap prior to killing an invisible monster, and the monster drops a wand that makes engravings vanish, it is most likely a wand of make invisible.

Invisibility and shops

One of the main disadvantages to invisibility is the hassle of shopping - you will be barred from entering or leaving unless you make yourself visible, which is especially troublesome if the source is a cursed item or gave invisibility that was permanent. 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; they can also try to teleport into and out of the shop.

Variants

SLASH'EM

In SLASH'EM, items can also be invisible as well - this includes the corpses of killed invisible monsters, but not any statues created from stoning them. Zapping an item(s) with a wand of make invisible will turn it invisible, as will dipping them in a potion of invisibility; dipping the item in a potion of see invisible or canceling it will render it visible again. There is a ¹⁄₁₂₅₀ chance that a randomly generated item will be created invisible.

The wand of wishing in the Castle is always invisible, but will always be found within its chest under normal circumstances. Mummy wrappings and gold can never be made invisible, and Sokoban boulders cannot generate invisible.

Invisible items mostly function the same as their visible counterparts, with some exceptions:

• An invisible blindfold or towel will still blind you if worn.
• An invisible mirror will not function when applied unless the monster has see invisible.
• Invisible scrolls and books cannot be read if you cannot see invisible.
• An invisible weapon has a +3 to-hit bonus against monsters that cannot see invisible.
• Invisible items cannot be stolen by a monster that cannot see invisible, with the exception of invisible body armor or a cloak worn on top of a visible t-shirt or body armor; no monster with a theft attack can normally see invisible.
• The disarm technique cannot be used if you cannot see the target's weapon.

Monsters will not pick up invisible objects if they cannot see invisible; however, this does not prevent them from moving to the item, with the result that they stand on top of it trying and failing to pick it up repeatedly.