Acid
Acid is a damage type that can be reduced by filling as many of your armour slots as possible. This protection comes at a price, as every piece of armour worn has a chance of being corroded.
Contents
Sources of Acid
Acidic damage can come from several sources.
Acidic Flesh
Some monsters have acidic flesh:
Hitting such monsters with a melee weapon (or any wielded piece of armour) has a 30% chance of corroding that weapon. If you are wielding nothing but wearing gloves, your gloves may corrode. If you are completely bare-handed, you will take 1d5 acid damage. Attacks other than punches (kicks, tail slaps, etc.) will not incur damage or corrosion.
Acid Spit
The following monsters can spit acid:
- Yellow draconian: 3d7
- Acid blob 3d7 (3d9 in Zot Defence)
- Oklob plant 3d7 (3d6)
- Oklob sapling 3d7 (3d3)
The above damage bypasses AC. The numbers are slightly adjusted when playing the Zot Defence variant. In addition to the above damage, acid spit causes 5 levels of "acid splash" damage (described below) which will harm you and can corrode your armour.
Acidic Melee Attacks
The following monsters have acidic melee attacks:
When struck by these monsters in melee, you will receive 3 levels of acid splash damage in addition to any regular (physical) damage the attack causes.
Slime Walls
Standing next to the walls of the Slime Pits will cause one level of acid splash damage for every level of depth, reaching 6 levels of splash damage on Slime:6. This damage is applied by every wall you are adjacent to: if you are surrounded by walls on Slime:1, you will receive eight separate level 1 splashes. Monsters without acid resistance will receive a flat 2d(level) damage from each wall.
Worshipers of Jiyva are unaffected by slime walls.
Thankfully, the acid splash from slime walls does not corrode items. But given how many monsters in the slime pits have corrosive attacks, this is of limited consolation.
Acid Splash
An acid splash will strike every armour slot - shield, helmet, body armour, gloves, boots, and cloak - with a chance of corroding each equal to the splash's level * 5%. If you are wearing a cloak, it has a 50% chance of negating a successful corrosion against the helmet, body armour, gloves, and boots slots (each rolled separately). This protection will not harm the cloak, which can only sustain damage when the cloak slot is corroded.
If you are not wearing armour in a given slot (excepting the shield slot), you will take 1d(splash level) damage (a cloak's 50% negation chance can also protect you from this). The fur mutation (trolls and felids) will reduce this damage by 20% per level of mutation.
2d(splash level) damage is then added to the above, meaning a splash can cause anywhere from 2d to 7d damage. Finally, the total damage is reduced by your acid resistance, as shown below.
Acid Resistance
Acid resistance protects you from any damage that gets past your armour. It is distinct from corrosion resistance, which protects your weapon and armour.
The sources of acid resistance are:
- Amulet of resist corrosion: rAcid+
- Cloak of preservation: rAcid+
- Tiamat's dragonskin cloak (50% chance per attack of rAcid+)
- Having the yellow scales mutation: rAcid+ for level 3.
The maximum resistance possible is rAcid+++.
Damage Reduction
| Resistance Level | Damage Taken (Player) | Damage Taken (Monster) |
|---|---|---|
| 1 | 50% | 0% |
| 2 | 34% | 0% |
| 3 | 27% | 0% |
Any fractional amount remaining is rounded down (if you get hit with 3 points of acid damage and you have rAcid+, you will only take 1 point of damage; if you have rAcid+++, you will take no damage). Acid resistance is effective against acid spit and splashes but does not reduce the damage received when punching an acidic monster.
All monsters with any degree of acid resistance are completely immune to acid damage.
Corrosion
Corrosion can cause items (weapons and armour) to lose a single point of enchantment. Corrosion comes from two sources: striking a monster that has acidic flesh (which only affects your wielded item or gloves), and acid splashes (which affect all worn pieces of armour, but not your weapon). Thankfully, the acidic walls of the Slime Pits no longer cause corrosion.
If an item is corroded, it still has a chance to resist the corrosion based on its enchantment value. The greater the absolute value of an item's enchantment level, the better its odds of resisting. For weapons, corrosion will only affect the weapon's damage enchantment; accuracy bonuses cannot be reduced, but will not defend the weapon.
| Enchantment (+ or -) | Resist % |
|---|---|
| 0 | 6% |
| 1 | 18% |
| 2 | 34% |
| 3 | 58% |
| 4 | 98% |
| 5 or more | 100% |
On top of that, the resist corrosion intrinsic (found on the amulet of resist corrosion and the cloak of preservation) gives you an additional 90% chance to resist corrosion. Dwarven items and crystal plate mail receive their own 80% resist chance as well.
An item's enchantment cannot be reduced to lower than -5 from corrosion, but it is rare for an item to be reduced below -4, since at that level, it has a 98% chance to resist further corrosion.
Finally, artefacts are completely immune to corrosion. When navigating the Slime Pits, a common strategy is to wear a set of whatever artefacts you've found in place of corrodible items. Alternatively, a set of "junk" items can be worn and later discarded; this is preferable to taking extra acid damage by wearing nothing. Similarly, a junk weapon can be employed when engaging early acidic monsters in melee; by the mid-game or later you should have a corrosion-immune weapon.
