Oilskin

Oilskin is an object property that can appear in multiple NetHack variants, and armor with the oilskin property will generally behave somewhat similar to oilskin cloaks while worn. Some variants also allow the property to be applied to certain containers, and such containers will behave similarly to oilskin sacks.

Implementation by variant

The exact details of the oilskin property varies fairly widely with the NetHack variant.

GruntHack

In GruntHack, oilskin is a property exclusive to armor and can occur randomly. Armor with the oilskin property can only be wished for if they have a base material of cloth.

Oilskin armor worn by a hero or monster acts as though it is permanently greased, and prevents the following effects of specific attacks that rely on grabbing the target in the armored area:

• Helms with the oilskin property will block the intelligence-draining bite attack of zombies and the tentacle attacks of mind flayers and master mind flayers.
• Cloaks, shirts and suits with the oilskin property function the same as normal oilskin cloaks do against holding attacks–such as the ones used by owlbears and the drowning attacks used by giant eels–if they are currently the outermost layer of armor being worn.

Non-cursed oilskin armor will always block attacks that require grabbing in some form, while cursed oilskin armor only has a ²⁄₃ chance.

DynaHack

In DynaHack, oilskin is a property exclusive to armor and can occur randomly, and armor with the oilskin property can only be wished for if they have a base material of cloth and the armor is not a magical item normally—only wishes from a wand of wishing can apply object properties. Note that a wish for "oilskin cloak of displacement" is parsed as a cloak of displacement with the oilskin property, which will fail: the proper syntax for an oilskin cloak that has the displacement property is "slippery cloak of displacement".

Worn oilskin armor functions as it does in GruntHack.

FIQHack

In FIQHack, oilskin is a property exclusive to armor and bags, and both can occur randomly. Properties cannot be wished for at all, and the oilskin property cannot be applied using a potion of wonder.

Worn oilskin armor is treated as permanently greased, and protects the wearer and their items from becoming wet as well as preventing monsters from grabbing or holding onto the hero if they target the worn armor. Oilskin bags protect their contents from becoming wet in addition to their base properties. Cursed oilskin items only have a ²⁄₃ chance of protection in both cases.

EvilHack

In EvilHack, oilskin is a property exclusive to armor and can occur randomly. Armor with the oilskin property can only be wished for if the armor is non-magical, made of cloth and has no other object properties: it is a valid property to wish for on toques or cloth elven helms, but not cloaks of magic resistance or dented pots.

Worn oilskin armor is treated as permanently greased, and functions mostly as it does in GruntHack. Monsters that target non-cursed oilskin items (including oilskin cloaks and oilskin sacks) to steal with item theft or charm attacks have a ³⁄₄ chance of failing to steal the item.

The Bag of the Hesperides is an artifact bag of holding that behaves like an oilskin sack does, though it does not have the actual oilskin property.

Hack'EM

In Hack'EM, oilskin is a property exclusive to armor and can occur randomly. Wishing for oilskin armor functions as in EvilHack.

Worn oilskin armor functions the same as it does in EvilHack, as does attempting to steal non-cursed oilskin items.

Hack'EM also adds the Wallet of Perseus, an artifact bag of holding from SLASH'EM, and grants it the same oilskin behavior as The Bag of the Hesperides in EvilHack.