In many variants of NetHack, an object property is a magical attribute associated with a non-artifact item which does not normally have that property; for example, a leather cloak of fire resistance would have the "fire resistance" property. Only weapons (including weapon-tools), armor, rings, and amulets can have object properties.
In GruntHack, randomly generated objects have a 1 in 100 chance of being generated with at least one property. A wish can apply a single non-detrimental property to the object wished for. Of those objects, each has a recursive 1 in 250 chance of having an additional property applied to it.
Wizards can sense object properties before they are identified, and see a "magical" prefix before the relevant properties are known.
- Reflection: Grants reflection. Not applicable to projectile weapons, boots, gloves, or helmets.
- Searching: Grants automatic searching. Not applicable to projectile weapons.
- Warning: Grants warning. Not applicable to projectile weapons.
- Stealth: Grants stealth.
- Telepathy: Grants extrinsic telepathy, as the helm of telepathy or amulet of ESP. Not applicable to projectile weapons.
- Fumbling: Grants fumbling.
- Hunger: Grants hunger.
- Aggravation: Grants aggravate monster.
- Fire: Deals double damage to non-fire-resistant targets; has a chance of destroying potions, scrolls, and spellbooks.
- Frost: Deals double damage to non-cold-resistant targets; has a chance of destroying potions.
- Vorpal: Single-handed weapons behead non-headless targets on a 1-in-20 chance (and jabberwocks 100% of the time), as with Vorpal Blade; double-handed weapons bisect small creatures and cut deeply into large creatures on a 1-in-20 chance, as The Tsurugi of Muramasa. Only applicable to bladed weapons.
- Thirsty: Drains life of non-drain-resistant targets, as Stormbringer and The Staff of Aesculapius.
- Detonation: Explodes upon hitting something after being fired or thrown. Only applicable to projectiles and launchers.
Note that in the very last development version of GruntHack, the extra fire and frost damage was changed from 2x to d6. This is the version of object properties that was incorporated in DynaHack. The version of GruntHack that can be played on grunthack.org does not have these changes.
- Fire resistance: Grants fire resistance.
- Cold resistance: Grants cold resistance.
- Drain resistance: Grants drain resistance.
- Speed: Grants extrinsic speed, as boots of speed.
- Oilskin: Permanently greased, as the oilskin cloak. Note: for wishing purposes in Grunthack, the base material must be cloth to get oilskin.
- Power: Sets strength to 25, as gauntlets of power.
- Dexterity: Grants a +(enchantment) bonus to dexterity, as gauntlets of dexterity.
- Brilliance: Grants a +(enchantment) bonus to intelligence and wisdom, as a helm of brilliance.
- Displacement: Grants displacement, as the cloak of displacement.
- Clairvoyance: Grants clairvoyance, as though wearing a cornuthaum as a wizard.
DynaHack works mostly similar to GruntHack, with some caveats:
- All players can sense object properties regardless of role.
- Vorpal no longer randomly generates.
- Weapons and weapon-tools get properties (level difficulty)/100 of the time.
- Armor get properties 1/100 of the time (similar to GruntHack).
- Jewelry gets properties 1/250 of the time (except for the Amulet of Yendor).
- Only magical wishes can apply an object property, and even then they can only be applied on non-magical base item. Oilskin doesn't count as an innate power, as it does not change player attributes; note that "oilskin cloak of displacement" is parsed as a cloak of displacement with the oilskin property, and thus counts as wishing for an object property to be applied. The proper syntax is instead "slippery cloak of displacement".
FIQHack object properties differ from those of GruntHack and DynaHack as follows:
- Vorpal doesn't generate randomly.
- Weapons and weapon-tools get properties (level difficulty)/100 of the time, much like DynaHack.
- Magical armor gets properties half as often as weapons, and jewelry gets properties 1/4 as often.
- Bags can generate with the oilskin property (which functions), with equal probability as weapons getting properties
- The following properties generate 10% as often: reflection, telepathy, speed, power, dexterity, brilliance, displacement
- Added properties:
- Lightning: Deals d6 to non-shock-resistant targets; has a chance of destroying wands.
- Shock resistance: Grants shock resistance.
- Mercy: autocurses and converts damage to healing, healing the opponent the equal amount as it would otherwise have damaged
- Carrying: increases carrying capacity by +10%, per item of carrying. Generates on armor only.
- Nasty: Deals +2d6 damage, but does 1d6 to the user on each melee hit or miss. Generates on melee weapons.
- Added container-only properties:
- Greed: Makes gold inside weightless, but causes 50% of attempts to take things out to fail.
- Discovery: Automatically reveals the base type of stashed items.
- Refrigeration: Prevents stashed corpses from rotting.
- You cannot wish for properties at all. However, you can add or remove properties using a potion of wonder (which can be wished for).
- Weapons can no longer generate with fumbling, but armor still can.
- "Properties applicable to most or all items" no longer includes projectile weapons, which only can have fire, cold, shock, thirsty or detonation.
- Detonations are fire-based by default; they become cold-based with weapons of frost, and lightning-based with weapons of shock.
- Price-wise, if an object has any property, its base price is increased by 50. In addition to this, each property double the overall price -- so if something's base price is 5, one property would have it at 110 ((50+5) * 2), two properties at 220 ((50+5) * 2 * 2), etc.
dNetHack uses a completely different version of object properties compared to most other variants. Objects with properties cannot be wished for and for the most part cannot be added to existing objects. They are primarily found in the initial inventories of certain monsters, and are also generated during the creation of certain special rooms and levels. Most properties appear in the item name when identified, but some will appear when unidentified as well.
Most weapon-enhancing properties add double damage of a certain type to the object when used as a weapon. Some of those come with a weaker form as well, which usually deals 2d6 damage instead. These bonuses only apply if you're making a valid weapon attack, so something like a flaming newt corpse grants no bonuses.
- Flaming: Deals double fire damage, which can destroy items in the target's inventory. If the target is considered fire-vulnerable (doesn't resist fire but does resist cold), deals an addition 1x damage for a total of 3x.
- Red-hot: A weaker form of flaming, dealing 2d6 damage instead. Can still destroy items.
- Freezing: Deals double cold damage, which can destroy items in the target's inventory. If the target is considered cold-vulnerable (doesn't resist cold but does resist fire), deals an addition 1x damage for a total of 3x.
- Frosted: A weaker form of freezing, dealing 2d6 damage instead. Can still destroy items.
- Shocking: Deals double electrical damage, which can destroy items in the target's inventory.
- Sparking: A weaker form of shocking, dealing 2d6 damage instead. Can still destroy items.
- Sizzling: Deals double acid damage, which can destroy items in the target's inventory.
- Acrid: A weaker form of sizzling, dealing 2d6 damage instead. Can still destroy items.
- Sparkling: Deals double magic damage (same as magic missile, checks player-style MR).
- Glittering: A weaker form of sparkling, dealing 3d4 damage instead.
- Misty: Deals double water damage, which is resisted by waterproofing (oilskin, white dragon scales, etc.). Deals an additional 1x damage to flaming monsters, earth elementals, iron golems, or chain golems.
- Damp: A weaker form of misty, dealing 2d6 damage instead.
- Psionic: Deals double damage, plus enchantment again for 3x enchantment and 2x base dice, to telepathic creatures. Has an addition 20% to trigger vs. non-telepathic but non-mindless creatures. Appears when telepathic (even when not blinded), or when fully identified. When not fully identified but seen via telepathy, appears as "whispering" instead of "psionic".
- Rustling: A weaker form of psionic, dealing 2d12 damage instead. Follows the same rules for vulnerable targets as psionic. Appears when telepathic only, even if fully identified.
- Anarchic: Deals double damage to non-chaotic targets. Only appears when the object is fully identified.
- Unruly: A weaker form of anarchic. Only appears when the object is fully identified.
- Concordant: Deals double damage to non-neutral targets. Only appears when the object is fully identified.
- Accordant: A weaker form of concordant. Only appears when the object is fully identified.
- Axiomatic: Deals double damage to non-lawful targets. Only appears when the object is fully identified.
- Apodictic: A weaker form of axiomatic. Only appears when the object is fully identified.
- Forge-hot: Deals 1d8 fire and 1d8 axiomatic damage.
- Crystalline: Deals 1d8 cold and 1d8 axiomatic damage.
- Arcing: Deals 1d8 shock and 1d8 axiomatic damage.
- Holy: When blessed, deals double damage to targets vulnerable to blessed items. Appears when blessed with "holy" replacing "blessed" in the object's name, but doesn't require the object to be fully identified.
- Consecrated: A weaker form of holy, dealing 2d6 damage instead. Appears with the same rules as holy.
- Unholy: When cursed, deals double damage to targets vulnerable to cursed items. Appears when cursed with "unholy" replacing "cursed" in the object's name, but doesn't require the object to be fully identified.
- Desecrated: A weaker form of unholy, dealing 2d6 damage instead. Appears with the same rules as unholy.
- Flaying: slices armor of struck targets, damaging a random piece of worn armor 1+d4 times. If the armor is reduced to giving no protection, the armor will be destroyed. If the monster has no armor left, living monsters without thick skin will "scream from the pain" and be slowed by 6 movement points. Only appears when the object is fully identified.
- Excoriating: a weaker form of flaying, only damaging worn armor by 1 point, and only slowing for 2 movement points. Only appears when the object is fully identified.
- Morgul: When used against you, embeds you with a morgul-blade shard. When used versus a monster, drains 1d4 hp and max hp from the target, bypassing drain resistance. Morgul shards abuse constitution, wisdom, and charisma, killing you if they bring all of those stats below their minimums.
- Morgul-shard: A weaker form of morgul, only giving you a shard if you didn't already have one in you. When used versus a monster, drains 1 hp and max hp.
- Wrathful: When used to kill a monster, gains +0.25 damage vs that monster type, maxing out at 4 kills and 2x damage. This damage applies to all monsters of that kind, based on factions (zombified, skeletons, etc.), racial flags (demons, humans, etc.), or just the exact same monster.
- Faded: The object is treated as shining, bypassing AC/DR of worn targets and always hitting insubstantial targets (shades, etc.).
- Vorpal: Can decapitate/bisect/etc. monsters with a 5% chance. The vorpal type is chosen based off the object's damage types. Weapons that are both slashing and piercing decapitate the target, only slashing bisect the target, only piercing pierce the target's heart or heart-equivalent, and bludgeoning smash the target flat. Only appears when fully identified.
These are exclusively extrinsic properties applied to items in any worn slot, including rings, amulets, and wielded items; offhanded items do not count.
- Flameproof: Grants fire resistance. Only appears when the object is fully identified. Flameproofed items are immune to fire damage.
- Coldproof: Grants cold resistance. Only appears when the object is fully identified.
- Voltproof: Grants shock resistance. Only appears when the object is fully identified.
- Acidproof: Grants acid resistance. Only appears when the object is fully identified.
- Magic-resistant: Grants magic resistance. Only appears when the object is fully identified.
- Disintegration-proof: Grants disintegration resistance. Objects with this property can't be destroyed by disintegration attacks, but can be destroyed by other armor shredding attacks. Only appears when the object is fully identified.
- Reflective: Grants normal reflection.
- Woolen: Grants both fire and cold resistance. Woolen items are immune to fire damage.
- Prayer-warded: Blocks effects that curse inventory items (such as the curse items monster spell). Also protects against mummy curses.
- Healing: Periodically heals the wearer (~0.5% to ~2% chance per turn). The healing effect occurs more often when the wearer is below 50% hp and when enemies are nearby. Heals up to 5d8 damage, but no more than 1/2 of the wearers lost HP will be healed. May heal sickness and sliming (5% chance per turn). Also known as "angel-haunted" when above 10 insight.
- Life-saving: If the wearer dies, their life will be saved. This property is lost after being triggered (but the piece of equipment itself is not harmed). Appears as "silver (or gold)-feather-encrusted" or "haloed" on objects that are not fully identified.
- Self-greasing: If the object has a 2.5% chance of greasing itself each turn. Only appears when the object is not greased. Appears as "grease-secreting" when above 10 insight.
- Anarchic: Grants double DR vs lawful and neutral attackers, but only half DR vs chaotic attackers. Only appears when the object is fully identified.
- Concordant: Grants double DR vs lawful and chaotic attackers, but only half DR vs neutral attackers. Only appears when the object is fully identified.
- Axiomatic: Grants double DR vs neutral and chaotic attackers, but only half DR vs lawful attackers. Only appears when the object is fully identified.
- Holy: When blessed, grants double DR vs. holy-hating attackers, but only half DR vs unholy-hating attackers. Only appears when the object is fully identified.
- Unholy: When cursed, grants double DR vs. unholy-hating attackers, but only half DR vs holy-hating attackers. Only appears when the object is fully identified.
- There are fewer object properties and they are only applicable to weapons and armor, with the exception of artifacts, unique items and dragon scales/scale mail.
- Items with object properties are less likely to be found in the dungeon, but can appear randomly on eligible magical items, and are more likely to occur with higher-level objects.
- The odds of an eligible item having a magical property are 1 in 150, and those odds improve with dungeon depth. For player monsters, the odds of their weapon having a magical property is 1 in 20 if they are of a high enough level or areencountered on the Astral Plane. Angelic beings flagged as M2_LORD have a 1 in 16 chance of their long sword being generated with a magical property.
- Regular armor and weapons obtained via sacrifice gift have a 1 in 8 chance of being generated with a magical property, provided the player has at least five Luck.
- There is a 1 in 100,000 chance of an eligible item randomly spawning with two properties.
- A players' starting inventory will never have an object property.
- Extrinsic properties that are applied to weapons or armor are active only when those objects are wielded/worn. With weapons, extrinsic properties work in the offhand whilst twoweaponing.
- Object properties can be wished for on an eligible item, but not on an already magical item (e.g. no wishing for a cloak of magic resistance and drain resistance). Object properties also cannot stack via wishing, e.g. you can't wish for a long sword of fire and venom.
- Changing a regular item with object properties into an artifact (e.g., dipping for Excalibur) will strip that item of its object properties.
- Wizards have an innate ability to 'sense' if an item is magical (much like a Priest knowing the beatitude of all items).
The table below lists all available magical properties, what items they can be applied to, and what their function is.
|Object property||Armor||Weapon||Armor attributes||Weapon attributes|
|Fire||X||X||provides fire resistance||does 1d5 + 3 of extra fire damage|
|Frost||X||X||provides cold resistance||does 1d5 + 3 of extra cold damage|
|Shock||X||X||provides shock resistance||does 1d5 + 3 of extra shock damage|
|Venom||X||X||provides poison resistance||does 1d2 + 10% chance of an additional 6-15 of extra poison damage, has a 10% chance of instakill by poison|
|Decay||X||provides drain resistance|
|Oilskin||X||acts as being permanently greased, can only be applied to cloth armor pieces (e.g. "oilskin cloth elven helm")|
|ESP||X||X||extrinsic telepathy when worn||extrinsic telepathy when wielded|
|Searching||X||X||extrinsic searching when worn||extrinsic searching when wielded|
|Warning||X||X||extrinsic warning when worn||extrinsic warning when wielded|
|Excellence||X||X||charisma adjustment equal to the enchantment||charisma adjustment when wielded based on BUC status (25/18/6 – blessed/uncursed/cursed)|
|Fumbling||X||extrinsic fumbling when worn|
|Hunger||X||X||extrinsic hunger when worn||extrinsic hunger when wielded|