Invisibility is an intrinsic with the effect that monsters without see invisible cannot see you. If you are invisible, they will have difficulty locating you and will usually miss when attempting to attack you unless you stay in one place.
Because monsters cannot easily locate an invisible player, an invisible player can fight an enemy that would otherwise be too powerful.
While the player is invisible, monsters incur a -2 to-hit penalty, and may strike at where they think you are rather than where you are.
Eating a stalker corpse while invisible will grant you see-invisible and make you permanently invisible.
An invisible player will be prevented from entering shops by the shopkeeper ("Invisible customers are not welcome!"). This can be circumvented by wearing a mummy wrapping, which will render you visible while you are wearing it, or by teleporting past the shopkeeper.
It is more difficult to get monsters that don't have see invisible to follow you, which may be a desired effect depending on the circumstances. Example: While invisible, it is harder to lure soldiers into the Castle trapdoors because soldiers cannot see invisible, or to lure wraiths to a non-graveyard level.
Normally a unicorn will avoid contact with the player, but this only works if the player is visible. A hostile unicorn will easily approach an invisible player and attack.
Medusa and mirrors
If you are invisible, having reflection or applying a mirror is ineffective against Medusa, and you cannot scare any monsters that do not see invisible by applying a mirror.
While invisible, displacement will not work on monsters that don't see invisible. However, displacement can be a more powerful defensive effect.
How to acquire
Ways to gain this intrinsic permanently or indefinitely:
- Eat stalker meat (corpse or tin) while already invisible through some other means. This method also grants you the see invisible intrinsic.
- Zap yourself with a wand of make invisible.
- Quaff a blessed potion of invisibility.
- Put on a cloak of invisibility.
- Invoke the Orb of Detection. Note: toggles invisibility unless it is already acquired as an intrinsic.
Temporary invisibility, 31 to 45 turns (more):
- Quaff a non-blessed potion of invisibility.
- Cast the invisibility spell on yourself.
Ways to manage this intrinsic
If you want to enter a shop, or for some other reason become visible, the easiest way is to find a mummy wrapping (mummies drop wrappings at a high rate) and wear it, which renders you visible (think "The Invisible Man"). The only two caveats are:
- The mummy wrapping counts as a cloak in terms of the slot that it takes up. If you have a reason to wear another type of cloak (such as a cloak of magic resistance to defend yourself against magic traps and other magical dangers), be careful when and where you wear the mummy wrapping. However, since the main reason to wear a mummy wrapping is to enter shops, and there are no traps in shops, this isn't a huge obstacle. Just be careful you don't forget to change back when you're finished shopping!
- Lastly, just like any other item in the dungeon, a mummy wrapping can be generated blessed, cursed, or uncursed, and have an enchantment level. Take caution and check the BUC status of the wrapping before wearing it, or you might be wasting your cloak spot, raising your armor class, and rendering yourself visible out of carelessness. Mummy wrappings are affected by scrolls of enchant armor and scrolls of destroy armor just like any other piece of armor.
Monsters can also be permanently made invisible by the wand, potion, mage monster spell, or by being a stalker or black light. Hostile monsters will use these items readily (regardless of BUC status) and have a chance of being generated with them. Peaceful and tame ones only do so if you can see invisible; this can be a problem if the potion only lets you temporarily see invisible.
There is no benefit to making pets invisible since it does not affect inter-monster combat. As an exception, an invisible floating eye's gaze will not paralyze pets that cannot see invisible; this is useful for pacifists.
If you recently heard a zap and find a wand that makes engravings vanish on a fresh kill, then the wand is most likely make invisible.
In SLASH'EM, the corpses of invisible monsters are also invisible
"You feel here an invisible <monster> corpse."