Based on the requests of our Patreon members we are sticking with some of those classic monsters from Dungeons & Dragons past. This week we bring forward a horrifying… bug? This strange monster is known as the Rust Monster, and as you may have gathered from its name… it has something to do with rust.

For all the monsters that have come and gone, it’s a little surprising that this strange looking creature has traveled through time, from the Greyhawk Supplement to the 5th edition. It certainly hasn't existed this long because of its good looks, but the unique ability to destroy metal. Finally we have a monster that doesn’t want to eat the flesh from your bones but rather is very interested in what you are wearing. This roach-like creature doesn’t bother trying to disarm you or hit for damage, instead, it focuses on corroding your weapon while it’s still in your hand.

Like the Owlbear we discussed last week, the Rust Monster is one of the original monsters created by Gary Gygax. Inspired by a toy he picked up to use in his game since most miniatures were for massive armies and not horrifying monsters, he created a creature that could not physically hurt you, but the mental damage it inflicted was far worse. In an interview with Dragon magazine, Gygax tells of how he came up with the Rust Monster.

Tony DiTerlizzi, 2013 — **Tony DiTerlizzi,** 2013

When I picked up a bag of plastic monsters made in Hong Kong at the local dime store to add to the sand table array … there was the figurine that looked rather like a lobster with a propeller on its tail … nothing very fearsome came to mind… Then inspiration struck me. It was a Rust Monster.
Dragon Magazine #88 (1984)

Owlbears, Rust Monsters, and Bulettes, Oh My!

OD&D - Rust Monster

No. Appearing: 1-2
Armor Class: 2
Move: 12”
Hit Dice: 5
% in Lair: Nil
No. of Attacks: 1
Damage/Attack: Special
Treasure: Nil

The Rust Monster was introduced in the Greyhawk Supplement (1974) and might be one of the more interesting monsters to be introduced in this edition. Not only is it more than just a typical monster that goes around murdering in a dungeon, but it also has a special way of dealing with adventurers that helps it stand out. We can only imagine the look of confusion at Gary Gygax’s table as he puts down his little toy Rust Monster and told everyone to roll their initiative… promptly followed by his uncontrollable giggling. They had no idea what was heading for them.

Unfortunately for the rest of the Dungeons & Dragons community that bought the Greyhawk Supplement there is no picture to giggle at and there is no information describing exactly what the Rust Monster even looks like. The closest we get to a description is that it looks like an “inoffensive creature” and that it is very fast, which is not exactly inspiring horrifying images of a bug-thing trying to eat your metal bits.

An encounter with the Rust Monster probably looked very different from table to table back then, but the mechanics of this monster would be similar. A group of adventurers is wandering around a dungeon when they stumble across 1 to 2 inoffensive but fast creatures. They decide this is a good time to put that fancy new magical sword to the test and the fighter goes to stab at this inoffensive looking creature. The blade then disappears into rust as it hits the monster, then it’s the Rust Monsters turn who inoffensively attacks the fighter turning all of their plate armor into rust immediately. We now have a naked fighter sprinting back to the party screaming about how the Rust Monster is invincible and that the magic-user needs to destroy it with a fireball.

Before we talk about what makes the Rust Monster so special, let’s look at their more generic statistics and how they stack up. Their AC is surprisingly high, as an AC 2 is equivalent to that of an umber hulk and even to some dragons. Their described “fast-ness” gives them a movement rate that allows them to keep up with most characters, if not chase them down. For such an inoffensive looking creature they also have a decent amount of Hit Dice, so that’s just one more surprise the party is in store for them when the fireball clears and these creatures are charging you, smelling that delicious sweet iron.

What truly makes the Rust Monster special though is their only attack that simply relies on them touching you. Their touch simply turns your armor into rust, this could be a metal shield, a holy amulet, or even a powerful magical artifact. It doesn’t matter what it is so long as it has that delicious ferrous material in it, meaning anything with iron content. Of course, that’s not the only problem when dealing with these annoying monsters. If you try to beat them away with your sword, your weapon turns to rust upon touching them, it doesn’t matter if it is magical or not.

All you are doing by using your iron weapons against a Rust Monster is simply feeding them. These creatures feed on the rust that was once a family heirloom passed down countless generations… Also, they can smell any iron-based metals and are attracted to it, so you might know to avoid them all the while they are specifically running after you, hungry for that delicious armor your fighter is wearing.

Basic D&D - Rust Monster

Armor Class: 2
Hit Dice: 5*
Move: 120’ (40’)
Attacks: 1
Damage: See below
No. Appearing: 1-4 (1-4)
Save As: Fighter 3
Morale: 7
Treasure Type: Nil
Alignment: Neutral
XP Value: 300

The Rust Monster appears in the Dungeons & Dragons Basic Set (1977) with nothing new, luckily for the Rust Monster, it gets a few updates in the updated Moldvay/Cook Basic Set (1981) and the BECMI Basic Set (1983). The original Basic Set from 1977 still has no information describing what this ‘unoffensive’ creature looks like and the limited information provided in OD&D is cut down even further. It’s not until the next Basic Set in 1981 that those who play Basic Dungeons & Dragons are able to gaze with horror at this monster and get a more detailed explanation of what exactly it is.

Dungeons & Dragons Basic Set, 1981 TSR Inc. — **Dungeons & Dragons Basic Set,** 1981 TSR Inc.

The Rust Monster is described as a giant armadillo with a long tail, it also has two feelers in the front that are more aptly described as long antennae. This description makes us question the ‘inoffensive’ tag that they had been described with previously, those who hail from Texas and similar southwestern states can attest that armadillos aren’t the prettiest of creatures. Combine that with an extra long tail and two long feelers on its face, that the artwork depicts as fuzzy, makes us worried it is going to feast on our face. Despite the overall sense of danger we get from this creature, at least there is no new lore that it likes to eat people, so that’s a plus.

With little no new information provided in the BECMI Basic Set, let’s go over a change that is featured in the 1981 and 1983 sets with regards to the Rust Monsters only attack. Hitting or being hit by the Rust Monster causes normal metal armor or weapons to immediately rust on contact and, as the description so helpfully points out, they become completely unusable. Thanks for letting us know a pile of rust doesn’t function anymore!

Now, that’s all as before, but this time we get clarification on magical items that might make you feel a teensy bit safer in fighting them. If you strike out at the Rust Monster, which we think actually makes you the monster, they just want a snack, your +2 magical sword will be reduced by 1 step to a +1 magical sword. It’s not so mean to the fighters, and in fact, your magical sword and magical armor get a chance to save against this type of effect! When you hit or get hit by the rust monster, the item targeted by the Rust Monster’s effect gets a 10% chance for every magical bonus to its stats to save against being turned into rust. This means that a +2 shield would have a 20% chance of not being reduced to a +1 shield when struck, while a +1 weapon would have a 10% chance of not becoming a mundane sword.

Now, typically we would end this edition here, but our Rust Monster gets a chance in the spotlight! In the 1983 Basic Set, there is a solo adventure to help teach new players how to play Dungeons & Dragons and features you assuming the role of a fighter and going around and clearing the nearby caves of baddies. The adventure is set up like a choose your own adventure and has you fighting goblins, ghouls, and the Rust Monster.

During the fight with this horrendous monster, it strips you of all your armor and weapons and then, as you stand their defenseless bracing yourself for the final blow… it loses interest in you and starts eating all the rust your equipment made for it. According to this adventure, Rust Monsters are not evil or mean, just hungry for rust, and have no intention of killing you. This is a great little tidbit hiding behind an adventure about the monster and how it operates inside of the world, it’s a little sad that this type of information wasn’t made available in the description of the monster. We might’ve saved even more of these strange monsters from being killed by murder hobo players!

AD&D - Rust Monster

Frequency: Uncommon
No. Appearing: 1-2
Armor Class: 2
Move: 18”
Hit Dice: 5
% in Lair: 10%
Treasure Type: Q (x10)
No. of Attacks: 2
Damage/Attack: Nil
Special Attacks: See below
Special Defenses: Nil
Magic Resistance: Standard
Intelligence: Animal
Alignment: Neutral
Size: M
Psionic Ability: Nil

Monster Manual, 1977 TSR Inc. — **Monster Manual**, 1977 TSR Inc.

Unfortunately for the Rust Monster, it doesn’t change much in this edition, though it at least makes it into the Monster Manual (1977). There are a few clarifications on several of its abilities and traits, so while things may not change, it is fleshed out just a tiny bit more.

Rust Monsters will only be found in dark, damp locations like dungeons, underground caverns, or potentially in a sewer. They spend their time wandering around, looking for food that, as mentioned previously, is made up of metal. For them, their ideal food is ferrous metals and they typically disregard metals like gold or silver, unlike the humanoids that wander the world murdering for it. The Rust Monster will hunt out these metal types, such as steel, iron, mithral, adamantine, and the like, being able to smell it from a fair distance away. Now we are sure they do other things other than just looking for food, like make more Rust Monsters, but we have no additional details. For all we know, they could be the life of the party at dungeon gatherings.

1st edition also uses the same rules as Basic does when it comes to how they deal with weapons and armor. Anything they touch with an antenna rusts away so long as it is a metal and anything you touch them with rusts away if it is a metal. If you are carrying out some magical items, you get that all-important saving throw to not lose it forever as it gets a cumulative 10% per magical bonus to the item. There is a big difference however, if the item fails the save, it immediately turns to rust. None of that wimpy being reduced by one so that your +2 sword would become a +1 sword. Fail that save and say goodbye to the magical flail your deity bestowed upon you. Good luck trying to explain that one.

The last bit of information you can squeeze out of the description is that Rust Monsters are easily distracted. When you decide to run away, and if your party is made up of only fighters clad in plate, you should run away, you can distract the Rust Monster from chasing you down. You’ll finally have a use for those caltrops you’ve been carrying around forever as you throw them on the ground and the Rust Monster will pause to have a snack. It’s a quick eater though, as it will only stop for a single round to munch on them. So get behind a door and wedge it shut. Now only if you had some caltrops…

We find out much more information about the Rust Monster in Ed Greenwood’s Ecology of the Rust Monster (Dragon Magazine #88, 1984). We know what the first thing you want to know about these Rust Monsters is, and don’t worry, we’ll let you know right after we talk about the important lore we learn about the Rust Monster. If you just can’t wait, skip this next paragraph.

Dragon Magazine #88, 1984 TSR Inc. — **Dragon Magazine #88,** 1984 TSR Inc.

Rust Monsters are highly dependent on their sense of smell, which makes sense as we know they can smell metals from a distance, but what you didn’t know is that if the Rust Monster can’t smell the object, they won’t know it is there. If some beautiful and tasty ferrous metal is hanging out in plain view, and for some reason the Rust Monster can’t smell it, it’ll completely ignore it and keep on walking past it. This ability to sniff out metals, and even to turn metals into rust, is thanks to a unique strain of bacteria that exists within the Rust Monster. It turns out, the Rust Monster is a host to this bacteria that produces sugar out of metals, more specifically ferrous metals, and then provides that nutrition to the Rust Monster. This, coupled with the energy of sunlight, which is weird as they hang out in dark, damp locations, keep the bacteria and the Rust Monster alive, rusting, and in good health. No one knows exactly what this bacteria is and it can’t live outside of the Rust Monster, but there are many interested in trying to grow their own and see what else they can do with such marvelous bacteria.

Now, for the information, you were dying to learn. If you skipped the paragraph above just so you could find this information out… well, we don’t know what that means about you, but here it goes. Rust Monsters reproduce by finding another one of their kind, the male Rust Monster will then begin making chittering noises. Because they aren’t very picky about who they propagate their species with, and that they mate very often, the female is more than likely down, and then 4 to 7 months later a baby Rust Monster will be born completely whole and ready to start devouring metals. It will stay with its mother for a few months before running off on its own and after a year of being alive, it’ll start chittering around to make more rust babies.

2e - Rust Monster

Climate/Terrain: Subterranean
Frequency: Uncommon
Organization: Solitary
Activity Cycle: Night
Diet: Metalalove
Intelligence: Animal (1)
Treasure: Q
Alignment: Nil [MC] / Neutral [MM]
No. Appearing: 1 -2
Armor Class: 2
Movement: 18
Hit Dice: 5
THAC0: 15
No. of Attacks: 2
Damage/Attack: Nil
Special Attacks: See below
Special Defenses: Nil
Magic Resistance: Nil
Size: M (5’ long)
Morale: Average (9)
XP Value: 270

Monstrous Compendium Volume Two, 1989 TSR Inc. — **Monstrous Compendium Volume Two**, 1989 TSR Inc.

The Rust Monster is forced to wait until the Monstrous Compendium Volume Two (1989) to get some love from 2nd edition and is later reprinted in the Monstrous Manual (1993). This edition goes to greater lengths to depict it more like an insect than in the previous versions, and outside of the metallic-like shell that covers it back, looks nothing like an armadillo. A yellowish-brown color, it now smells like wet, oxidizing metal. Yum. It has two freakishly long antennae extending out from its face, its legs look like they belong on a cricket, and its tail has a hammer or paddle-like extension in the back. It’s a very strange creature, but the text assures us it is still very inoffensive and just wants to eat.

This edition goes to great lengths to paint this monster as not an evil creature, but a misunderstood one that just can’t help its nature. Due to its ever-present hunger, it has little interest in anything that doesn’t have metal. In fact, it is quite excited when it smells metal, especially if it is forged and worked metal like your fighter’s plate armor. They prefer eating refined metal armor than just chunky raw ore, but that doesn’t make them an evil creature. Wouldn’t you rather have a meal from a fine dining restaurant than have to eat prison food?

Of course, you would, and your shiny +1 sword is a gourmet meal to the Rust Monster. If you don’t happen to carry any metal, looking at you wizards, it won’t bother you but will sniff at you curiously. If you have nothing of interest, read: metal food, it will leave you alone and continue looking for scrumptious morsels to feast on. Now if you’re a dwarf, these creatures are like roaches to you, a pest that you want to eradicate. Dwarves aren’t known to be the sharing type, and since our Rust Monster eats the precious metals they use in their forges, they must be eliminated with extreme prejudice.

Monstrous Manual, 1993 TSR Inc. — **Monstrous Manual**, 1993 TSR Inc.

Little changes for the Rust Monster, attacks against them with metal weapons will turn those same weapons into rust. Attacks by the Rust Monster don’t hurt you but do leave you naked as your armor turns to rust. All magical metal items get a chance of not turning to rust on contact, the same as the previous edition. The largest change is that now, there is a 30% chance per round that a Rust Monster will simply stop mid-combat to snack on any rust that has formed as you tried to keep it away. It doesn’t matter how much of your stuff it has turned to rust, or how much more stuff you have that would be tasty, it will always take one round to consume all the rust around it.

For the sake of argument, let’s say you kill a Rust Monster because there is no driving these creatures away. They are apparently too stupid to have a sense of self-preservation and only have the thought to consume more and more rust. If you kill one of these innocent and pure creatures, what type of treasure can you expect? Well, there is a very high likelihood you’ll find rust… from your own equipment. But also gems! Rust Monsters don’t collect treasures and don’t have a use for gems that are embedded into sword hilts or helmets, leaving them scattered around on the floor. Maybe their young like to play with gems like they are balls when they aren’t gorging themselves on rust.

Speaking of their young there is a small chance that you could find a happy little family of Rust Monster, with the parents having a single offspring with them. Being an only child has its challenges, but at least it won’t have to share its meals. The kiddo may only be at the half-strength of a normal Rust Monster, but it eats as if it is fully grown. Creatures that eat organic materials and leave behind the metals, such as carrion crawlers and gelatinous cubes, are the Rust Monsters’ best friends, following behind and eating the discarded metals.

The Planes of Law, 1995 TSR Inc. — **The Planes of Law**, 1995 TSR Inc.

The last new tidbit of information you can glean about the Rust Monsters takes us off the Prime Material Plane and out into the Outer Planes. On the first layer of the plane of Acheron, Avalas, you might stumble across a strange sight. That of an insectoid-dragon with its tendrils turning the metal cubes of Acheron to rust for it too greedily devour. These Rust Dragons are supposedly the imago, or adult, form of the Rust Monster, with the Rust Monsters we all know and love, well maybe not love, are the larva forms of the Rust Dragons.

Rust Monsters will somehow journey, once they get incredibly old, to the Outer Plane of Acheron where they will gorge themselves for a whole year on the metal cubes located on Avalas. After a year passes, they will then spin themselves a metallic web and will go into the pupa stage inside of their chrysalis where they will undergo a metamorphosis for three years. Upon emerging out of their metal spun shell, they will take on the form of a Rust Dragon and begin a long life of happily gorging themselves on the metal cubes of Acheron.

3e/3.5e - Rust Monster

Medium Aberration
Hit Dice: 5d8+5 (27 hp)
Initiative: +3
Speed: 40 ft. (8 squares)
Armor Class: 18 (+3 Dex, +5 natural), touch 13, flat-footed 15
Base Attack/Grapple +3/+3
Attacks: Antennae touch +3 melee (rust)
Full Attack: Antennae touch +3 melee (rust) and bite -2 melee (1d3)
Space/Reach: 5 ft./5ft.
Special Attacks: Rust
Special Qualities: Darkvision, scent
Saves: Fort +2, Ref +4, Will +5
Abilities: Str 10, Dex 17, Con 13, Int 2, Wis 13, Cha 8
Skills: Listen +7, Spot +7
Feats: Alertness, Track
Climate/Terrain: Underground
Orgnization: Solitary or pair
Challenge Rating: 3
Treasure: None
Alignment: Always neutral
Advancement: 6-8 HD (Medium); 9-15 HD (Large)
Level Adjustment: -

Monster Manual, 2003 WotC — **Monster Manual**, 2003 WotC

The Rust Monster moves on up in this edition and gets introduced in the Monster Manual (2000/2003). To one of the authors at Dump Stat, the Rust Monster looks even more like an insect than in the previous versions, while the other author thinks the Rust Monster now looks like an ugly mess of skin pudding. You’ll have to make your own opinions about this questionable rendition of this monster.

Looking at the artwork, Rust Monsters now have the coloring of reddish hues into a yellowish-brown color. It very much looks like it is rust, whether or not it is because of years of eating rust has stained its body, we aren’t sure. It could be you are what you eat, it could also be that it is a very messy eater and just needs a bath to wash all the rust off its carapace.

Dragon Magazine #346, 2006 Paizo Publishing — **Dragon Magazine #346,** 2006 Paizo Publishing

3rd edition also introduces something new for the Rust Monster, it can now hurt you by biting on to you for a paltry 1d3 points of damage. Of course, its primary attack, corroding all your metal items, is now listed as a “Rust” attack. So much for originality in naming the ability, but it gets the point across. Also, we finally have a measurement of how much metal can be rusted in one attack, and that is a 10-foot cube of metal. That is a crap-ton of metal to destroy in one blow.

Magic items no longer get a percentage chance of being affected, rather you must make a Reflex saving throw or watch as your beautiful set of ancient plate armor from a lost civilization that gives you the powers of gods rusts away into a pile of delicious food. We suppose if we just watched what could only be called a priceless artifact get turned into chowder, we’d be a bit upset and murderous too.

Draconomicon: The Book of Dragons, 2003 WotC — **Draconomicon: The Book of Dragons,** 2003 WotC

Now, we aren’t opposed to change, in fact we enjoy seeing how monsters augment and morph throughout the many editions of Dungeons & Dragons, even if we bitch about it quite a bit. We only mention this because of the great injustice that 3e piles onto the Rust Monster who just wants to eat all your delicious goodies. In the Draconomicon: The Book of Dragons (2003), there is an entry for the Rust Dragon and in it… they mention the Rust Monster. You might think that that is appropriate, obviously, the Rust Dragon is just the adult stage of a Rust Monster, but no. This entry goes on to say that the idea that the Rust Dragon is from the Rust Monster is simply the “ravings of deranged lunatics.”

This injustice stands for three long years until Dragon #346 (August 2006) and the article Ecology of the Rust Monster is released and in it, they finally admit that there is probably some connection. The entire article takes a new look at the Rust Monster and is a great read that provides an interesting spin on how the Rust Monster rusts away metal. Instead of using bacteria to destroy metal, a Rust Monster uses its paddle tail to breath in lots and lots of carbon dioxide where it’s body then turns that into pure oxygen. Across its feather-like tentacles and all over its body are tiny little nodules that the Rust Monster can use to eject pure oxygen, along with some pseudo-magic ability, to immediately oxidize and destroy metals, which explains how the Rust Monster can destroy gold, silver, and other non-ferrous metals.

Apart from their new explanation about the Rust Monster’s abilities, we also get information about how the Rust Monster has several different origin stories, with the widely spread one being that they were created by a god who was scared of technology. They created the Rust Monster as a response to the threat of greater technologies, and all that remains of their realm is a rusty wasteland as these cute little monsters destroyed absolutely everything. There’s a lesson to be learned in there somewhere, but we can’t stop to think about that as the article mentions two other important pieces of information.

The first being that there are different versions of the Rust Monster that reside in different environments, from the shaggy, blue Frostfell Rust Monster that destroys metal by super blasting it with cold and freezing it so it shatters, to the khaki-hued Waste Rust Monsters that turns metal into sand. These different variations of the Rust Monsters can be found in deserts, tundras, swamps, and other geographical regions, all giving the Rust Monsters different ways of destroying your favorite sword.

The second piece of information worth talking about is their relationship to dragons and Rust Dragons in particular. Now you might be groaning for our, at least one of the author’s, strange obsession with dragons, but hear us out. There is a small section that briefly mentions that the Rust Monsters might be attracted to the metallic dragons due to their affinity to specific metals. This has led to Rust Monsters, maybe, messing around with some of the metallic dragon eggs, either by tainting the egg itself and transforming it into a Rust Dragon or that the Rust Monster eats the contents of the egg itself, mistaking its metallic egg for metal to be feasted on, transforming them into a Rust Dragon. This is a fascinating look at how magical creatures could interact with each other, though we vastly prefer 2e’s version of events where they spun themselves a comfy metal cocoon and emerged as a pretty insect-dragon with cute little insect wings.

4e - Rust Monster

Level 6 Skirmisher
Medium Natural Beast / XP 250
Initiative +10 / Senses Perception +5; low-light vision
HP 66; Bloodied 33
AC 20; Fortitude 16, Reflex 21 Will 17
Speed 8
Bite (standard; at will) +11 vs. AC; 1d10+5 damage, and if the target is wearing heavy armor, the armor is rusting until the end of the encounter. While the armor is rusting, the target takes a cumulative -1 penalty to AC, to a maximum penalty of -5.
Dissolve Metal (standard; encounter) Reliable. Targets a creature wearing or wielding a rusting magic item of 10th level or lower or any non-magic rusting item; +9 vs. Reflex; the rusting item is destroyed.
Rusting Defense (when the rust monster is hit by a weapon attack; at will) The weapon used in the triggering attack is rusting until the end of the encounter. While the weapon is rusting, the target takes a cumulative -1 penalty to damage rolls on attacks that use the weapon, to a maximum penalty of -5.
Residuum Recovery A rust monster consumes any items it destroys. The residuum from any magic items the monster has destroyed can be retrieved from its stomach. The residuum is worth the market value of the item (not one-fifth the value).
Alignment Unaligned / Languages -
Str 8 (+2) Dex 20 (+8) Wis 15 (+5) Con 10 (+3) Int 2 (-1) Cha 12 (+4)

Monster Manual 2, 2009 WotC — **Monster Manual 2**, 2009 WotC

Unfortunately for the fan-favorite Rust Monster, it is forced to wait 2 long years before it arrives in 4e with the release of the Monster Manual 2 (2009). Ok, so the Rust Monster may not be a fan favorite, but it’s probably a favorite of DM’s everywhere, that’s for sure. We usually complain that the 4th edition provides little to no information about the monster we look at, but it’s the exact opposite for our favorite monster, Rusty. We are introduced to not only the Rust Monster but a Young Rust Monster Swarm and the magic loving Dweomer’s Eater. We still won’t forgive them for putting the Rust Monster in the second book of monsters, but it’s a start.

The Rust Monster’s abilities get new fancy names in 4th edition, but they remain the same in what they do. The Rust Monster still isn’t the smartest creature you’ll run into, but it remains one of the hungriest. When encountered, it will immediately head towards the party member wearing and or wielding the most metal, that it can see. See!? Now, Rust Monsters can see your metal, which means no layering dung on your armor in a desperate attempt to not be smelled.

Now, when it sees all that beautiful metal, which is typically worn by you, Mister Fighter, and it begins to charge you down, how should you respond? If you’ve never run into one of these creatures before, you’ll probably do what you do best… swing your big old sword at it until it dies or you die. By now we all know what happens. Hit Rusty or get hit by Rusty and your fancy metal starts to rust.

The difference now is that the game has become a kinder, gentler game, which makes us a bit sad. Your magical stuff no longer immediately rusts into a small snack for the Rust Monster to feast upon. It will continue to rust over the length of the encounter and it is possible that it too will become a pile of rust, but losing it immediately on a failed save is no more. While its horrifying to watch your Mace of Disruption slowly disintegrate before your eyes throughout an encounter, it’s better than watching it dissolve in your hands in 6 seconds.

In fact, their Dissolve Metal attack only works on equipment that can rust as the statblock specifies “…wearing or wielding a rusting magic item… non-magic rusting item…”. This means if you make a sword completely out of silver for those werewolves, it’ll be fine, at least how we are reading it. Except there’s a small hang up to that, as their defensive ability Rusting Defense has no text about the weapon being able to rust, it simply states that any weapons hitting it take a penalty the more the Rust Monster are struck as the weapon ‘rusts’. At the end of the encounter, your weapon stops rusting.

Of course, what happens if you had used a Mace of Disruption and it died during this knockdown fight with the Rust Monster? That brings us to the biggest change for the Rust Monster, more specifically its Residuum Recovery ability. Unlike many creature abilities, this one doesn’t provide any benefit for the creature, but it sure as hell provides the player with a massive benefit. When Rusty eats the pile of rust that was once your amazing mace of death, not surprisingly it ends up in its stomach. Now, after eating its fill of metal, the 4th edition Rust Monster will scurry off, retreating to digest its meal, and we bet most likely he’ll take a nap. Now, we aren’t suggesting that you track down and kill poor little Rusty with extreme prejudice, but if you do, you have a chance of saving your precious items.

By slicing the Rust Monster open, you can cut open its stomach, and scoop out the ‘residuum’ that was once your all-powerful weapon and you have a chance to ‘rebuild’ it. 4th edition provides a very handy way of doing so with the Create Magic Item feat which will allow you to recreate the lost item from the residuum. The text of the Rust Monster strongly suggests that the DM allows the player to be able to recover their lost items. It goes on to say that you can make the player suffer for a bit by making them use a plain old weapon before they find the time or person to recreate the item. A newer DM probably thinks this is a great idea, but grognards might start screaming bullshit upon reading this. This, while annoying, is not quite the same awfulness of past editions and just makes the Rust Monster an annoyance and not that dangerous.

We are also introduced to the Young Rust Monster Swarm and Dweomer Eater. The swarm is an interesting creature, when you think of a swarm, you think about a large number of creatures attacking as one. Since Rust Monsters only have 1 to 2 young, the question is how do you find that many Young Rust Monsters? Do they all go to the same Junior High School and once they hit those teenage years become an unruly pack of angry and disillusioned Rust Monsters? No matter how it happens, it isn’t fun for the poor group that runs into the swarm. Look no further than its primary attack, Swarm of Teeth to understand just how deadly the swarm is. The name alone sounds horrible, and if you happen to be wearing heavy armor, your day truly is horrible. Though we should point out, no equipment can be destroyed by the swarm, you simply take a penalty until the end of the encounter.

Next up is the Dweomer Eater, which is every sentient magic item worst nightmare. Not only do they love the taste of metal, but their favorite side dish is arcane energy. Its Magic Consumption defensive ability sucks the magic out of a weapon when you strike at it, of course you can sit back and relax because it comes back by the end of the encounter. If the Dweomer Eater can turn your item to rust and devour it, repeat the previous steps of murdering it in cold blood, dissecting it, and then scooping out your residuum. At this point, it's worth pointing out that when you sold stuff in 4e, you’d get about one-fifth the value of the item, not so with this residuum as you can sell this magical rust for its full market value. You can go up to a merchant with rust in hand, give a small shrug and they’ll pay you for the total amount of that Mace of Disruption you lost. You can then turn around and spend that exact amount the merchant gave you and buy a brand new Mace of Disruption free of all rust, it’s like you never lost your mace at all… which… is… let’s move on to a different topic!

Dragons! Oh wait, there are two Draconomicons (2008/2009) in 4e and neither one has information on the Rust Dragon? Sigh. We regret to inform you, dear reader, that the Rust Dragon has been removed from Dungeons & Dragons, and every baby Rust Monster’s dreams of metamorphosing into a fearsome and deadly dragon is just rust in the wind.

The last thing we should mention about the Rust Monster doesn’t actually have to do with the Rust Monster directly. There is a section at the end of the Rust Monster’s stat blocks called “A Guide to Using Rust Monsters” that has some good pointers in there but also creates a very ‘safe’ atmosphere. The good pointers are that if you include a Rust Monster, come up with ways for the adventurers to carry on their adventuring day, otherwise, the players will feel like they must end the action and return to town to buy new weapons. This could be by providing less optimal equipment early on in the dungeon that the PCs could use or letting them fashion makeshift weapons out of what they can find. It makes sense and is important for DMs to think about.

One of the problems it creates, while not necessarily a problem of the game itself, is that this turns the Rust Monster into a very ‘safe’ encounter. There is no risk of losing your equipment, really its more of an annoyance than anything else, and the players, if they want their stuff back must simply go to town, sell some rust and get all their equipment back. All it took was time not playing the game for them to do this. While we understand this was done because of the importance of the magic item treadmill in 4e, which was also very much present in the previous editions, the Rust Monster stops being the threat it once was and just becomes annoying to deal with.

5e - Rust Monster

Medium monstrosity, unaligned
Armor Class 14 (natural armor)
Hit Points 27 (5d8+5)
Speed 40 ft.
STR 13 (+1) | DEX 12 (+1) | CON 13 (+1 ) | INT 2 (-4) | WIS 13 (+1) | CHA 6 (-2)
Senses darkvision 60 ft., passive Perception 11
Languages -
Challenge 1/2 (100 XP)
Iron Scent. The Rust Monster can pinpoint, by scent, the location of ferrous metal within 30 feet of it.
Rust Metal. Any non magical weapon made of metal that hits the rust monster corrodes. After dealing damage, the weapon take 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.
Bite. Melee Weapon Attack: +3 to hit, reach 5 ft., one creature. Hit: 5 (1d8 + 1) piercing damage.
Antennae. The rust monster corrodes a non magical 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 mental 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.

Monster Manual, 2014 WotC — **Monster Manual**, 2014 WotC

The Rust Monster is introduced for 5th edition in the Monster Manual (2014) and it is nerfed. Massively nerfed. Outrageously nerfed. 5th edition strips away everything that makes the Rust Monster a creature worth fearing, causing grown goliaths to weep like children when their favorite toy is taken away. It now has a mediocre Armor Class, hit points that a 2nd level character could wipe out in a few turns, and the same CR as a giant goat. All this plus the fact that the picture of the Rust Monster is worse than the previous editions, we have to wonder… where was the love for the Rust Monster?

The most damaging blow to the Rust Monster’s greatness involves its Rust Metal ability. No longer does this ability have any effect on magic items. That’s like taking away a dragon’s breath weapon attack or saying that griffons have wings but can’t fly. While you could easily strip the Rust Monster of its ability to destroy magic items and claim it is for game balance as magic items are so rare in 5e, that doesn’t explain the rest of the stat block. If you attack with your non-magical weapon, you get five hits in with it before it is destroyed completely… Which probably isn’t going to happen as four average attacks with a shortsword (d6) with just a +3 modifier will end up with you dealing 25 points of damage to the Rust Monster, and because you are an adventuring party of 4, you don’t even have to hit that many times. This just means that your weapon will, instead of being destroyed, just have a permanent penalty to them until you toss it away and buy a new one… or steal the dead goblin’s shortsword. We’d say that this is more of an annoyance than having your weapon destroyed in a hit as then you are just walking around with a faulty weapon instead of improvising.

Of course, weapons aren’t the only things that a Rust Monster is interested in as armor can be made of metal too. When metal is struck by the Rust Monster, you get a chance to avoid the equipment getting touched by the Rust Monster that is pretty easy to make. If you have no modifier to your Dexterity, there is a 50% chance you won’t get touched by the Rust Monster, and then the Rust Monster’s turn is over and then you wail on it and it dies. If you are unlucky and your armor gets touched, it takes a minus to the AC bonus it provides and is only destroyed if it is reduced to a bonus of 0. Shields would take two turns to destroy completely while most armor would take anywhere from 3 to 8 turns to destroy, though again… it’ll pry take a lot longer as it is such a low DC to make.

Looking at the lore for the Rust Monster, we are disappointed that there is no mention of its rightful place as the larva stage of a Rust Dragon, but at this point we weren’t holding our breath. The lore stays pretty much the same, though it does specify the Rust Monster is only interested in ferrous metals, which still includes mithral or adamantine, but they no longer can eat silver, gold, and other metals.

The Rust Monster also gains the Iron Scent ability which allows it to smell metal, which is better than in 4th edition at least, but its range is reduced from 90 feet to a mere 30 feet. Rust Monsters are still inoffensive, even if they aren't described as such anymore, and aren’t likely to attack you unless it smells some delicious ferrous metal on you. If you treat a Rust Monster with love and respect, it could become a pet or a companion. That does mean that if your druid won’t let you kill the Rust Monster for slightly damaging a random weapon you found lying around on the ground, the druid will have to keep a constant eye on their new pet and ensure it doesn’t eat the plate-clad paladin while they are taking a nap.

The Rust Monster was created from a random toy and its legacy had a lasting impact on every character that would run into it. Adventurers would flee in fear from it and, while it was incredibly weak, created an interesting challenge that a party had to face with very real consequences for not planning properly. Throughout the editions, the Rust Monster was slowly pulled back until the main ability that makes it fearsome ends up being pretty much useless. By 5th edition, only low-level characters need to be careful if they encounter one as they probably don’t have magical items yet. But then again, losing your longsword at level 2 isn’t that big of a deal. With the way the gold economy works in 5th edition, what else do you have to spend your money on?

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