Rust Monster — D&D 5e Monster Stats (CR 1/2)

Q: What are Rust Monster's AC and HP in D&D 5e?

Rust Monster has an Armor Class of 14 and 27 hit points (5d8+5).

Q: What Challenge Rating is a Rust Monster?

Rust Monster is CR 1/2, worth 100 XP — roughly a fair fight for a party of four characters of a similar level.

Q: What type of creature is Rust Monster?

Rust Monster is a medium monstrosity, alignment unaligned.

Armor Class14

Hit Points27 (5d8+5)

Speed40 ft.

ChallengeCR 1/2 (100 XP)

STR

13

(+1)

DEX

12

(+1)

CON

13

(+1)

INT

2

(-4)

WIS

13

(+1)

CHA

6

(-2)

Sensesdarkvision 60 ft., passive Perception 11

Special Abilities

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. Nonmagical 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, its 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.

Running Rust Monster in an encounter

As a CR 1/2 threat worth 100 XP, Rust Monster is a fair challenge for a party of four at a comparable level. With no legendary actions it works best in numbers or paired with support, where its CR 1/2 rating won't be burned down in a single round. Use the XP value with the encounter builder to slot it into a balanced fight.

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