Rust Monster

Source: SRD / Basic Rules

title: Rust Monster
![](https://raw.githubusercontent.com/5etools-mirror-2/5etools-img/main/bestiary/tokens/MM/Rust%20Monster.webp#token)
*Medium monstrosity, Unaligned*
 
- **Armor Class** 14 (natural armor)
- **Hit Points** 27 (`5d8 + 5`)
- **Speed** 40 ft.
 
|STR|DEX|CON|INT|WIS|CHA|
|:---:|:---:|:---:|:---:|:---:|:---:|
|13 (+1)|12 (+1)|13 (+1)| 2 (-4)|13 (+1)| 6 (-2)|
 
- **Proficiency Bonus** +2
- **Saving Throws** ⏤
- **Skills** ⏤
- **Senses** darkvision 60 ft., passive Perception 11
- **Languages** —
- **Challenge** 1/2
 
## Traits
 
***Iron Scent.*** The rust monster can pinpoint, by scent, the location of ferrous metal within 30 feet of it.
 
***Rust Metal.*** Any nonmagical weapon made of metal that hits the rust monster corrodes. After dealing damage, the weapon takes a permanent and cumulative −1 penalty to damage rolls. If its penalty drops to −5, the weapon is destroyed. Non magical ammunition made of metal that hits the rust monster is destroyed after dealing damage.
 
## Actions
 
***Bite.*** *Melee Weapon Attack:* `+3` to hit, reach 5 ft., one target. *Hit:* 5 (`1d8 + 1`) piercing damage.
 
***Antennae.*** The rust monster corrodes a nonmagical ferrous metal object it can see within 5 feet of it. If the object isn't being worn or carried, the touch destroys a 1-foot cube of it. If the object is being worn or carried by a creature, the creature can make a DC 11 Dexterity saving throw to avoid the rust monster's touch.
 
If the object touched is either metal armor or a metal shield being worn or carried, it takes a permanent and cumulative −1 penalty to the AC it offers. Armor reduced to an AC of 10 or a shield that drops to a +0 bonus is destroyed. If the object touched is a held metal weapon, it rusts as described in the Rust Metal trait.

Environment

underdark