Invisibility can be granted by the spell of the same name, or by various magic items.
It causes monsters without ability to see the player to have reduced chance to hit. Ranged attacks will be directed generally in player's direction, but usually not in the player's square (greatly reduces chance to be hit by a such attack). The spell will not, however, help the player to escape the attention of the monsters, as they can always see the player.
Invisible monsters (against a player without ability to see them) aren't shown on the map, are harder to hit and little is revealed about their state ("you hit/miss it" is the only information revealed for most attacks). Gods who appreciate killing still count invisible monsters.
Invisibility player spell
|This spell hides a creature from the sight of others. While invisible you will gain magical contamination, which may eventually cause enough glow to make you visible again.|
Casting this spell allows you to project a single-target enchantment beam; the first creature in the beam's path automatically becomes invisible. The most obvious use of this is to make yourself invisible by targeting it in direction ".". Doing so incurs 1d2 points of magic contamination.
For the player, Invisibility effects from whatever source have a duration of 14 + 1d(power) turns (subject to a hard cap of 100). When you become invisible, any current Backlight effect is dispelled.
Equipping a ring of invisibility, cloak of darkness, robe of Night or an artifact with the Invisibility power allows you to turn Invisible with a power based on your Evocations skill. (You can also cancel invisibility from any source with 100% reliability if you have such an item equipped.)
The invisibility evocation has a power of ((2 * (Evocations skill)) + 5), and incurs 1d3 points of magic contamination when activated.
Wand of invisibility
See Wand of invisibility for the item properties.
For the player, a wand of invisibility operates in much the same fashion as the spell (including the 1d2 contamination effect). The power of a wand of invisibility, like any other wand, is 15+2.5×Evocations.
Potion of invisibility
See Potion of invisibility for the item properties.
Like all potions, potions of invisibility operate with a fixed power rating of 40. Unlike the wand, spell, or evocation, drinking a potion of invisibility does not incur automatic magic contamination.
Invisibility applied to monsters from any source, regardless of power, has a duration of 16 to 56 of the monster's turns. Many spellcasters can cast Invisiblity. They will generally not to do so unless you are in line of sight, so you will at least see them before they become invisible. However, the following monster are innately, permanently invisible:
Several things can negate invisibility. Most notably, glow from any source, including the Corona spell, sticky flame, or magical contamination, will make any invisible being visible. Also, stepping in water while not flying will cause you (or a monster) to become temporarily visible.