Rust Monster

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.

Iron Scent. The rust monster can pinpoint the location of ferrous metal within 30 feet of itself.

Actions

Multiattack. The rust monster makes one Bite attack and uses Antennae twice.

Bite. Melee Attack Roll: +3, reach 5 ft. Hit: 5 (1d8 + 1) Piercing damage.

Antennae. The rust monster targets one nonmagical metal object—armor or a weapon—worn or carried by a creature within 5 feet of itself. Dexterity Saving Throw: DC 11, the creature with the object. Failure: The object takes a −1 penalty to the AC it offers (armor) or to its attack rolls (weapon). Armor is destroyed if the penalty reduces its AC to 10, and a weapon is destroyed if its penalty reaches −5. The penalty can be removed by casting the Mending spell on the armor or weapon.

Destroy Metal. The rust monster touches a nonmagical metal object within 5 feet of itself that isn’t being worn or carried. The touch destroys a 1-foot Cube of the object.

Reactions

Reflexive Antennae. Trigger: An attack roll hits the rust monster. Response: The rust monster uses Antennae.