When a game has as wide a range of monsters as Dungeons and Dragons, it’s inevitable that some enter common usage, and some are forgotten.  In the weird in-between area, though, there are the weird ones that are remembered and recognized for their strangeness but either go unused or get thrown in for giggles without really putting them to good use.  So today, I’m going to talk about how these monsters are not only cool but I’m also going to talk about how they can add a lot to the campaign both as an encounter and as the centerpiece for an adventure.  A quick disclaimer: None of the monsters from my last list are going to be on here, even if the Nothic would be a perfect fit.  Also, I’m staying away from enemies that are tied to a specific larger threat because they have adventure hooks built in, which is why the cranium rats aren’t included.  Also (again) the Flumph isn’t on here because I’m waiting to put them on a different list.  So, with that in place, let’s start with…

5. The Behir (CR 11, Monster Manual)

For the longest time I thought that these guys were just another giant monster to throw into a dungeon when you needed something big and scary, but the reality is that it’s a lot more than that.  First off, just look at it.  You see how it looks like a snake with legs?  Well it only uses those legs to climb up and down cavern surfaces like a spider.  When it’s chasing someone down a stretch of cavern it rolls its legs under itself and slithers at a rapid speed like a super quick snake with alligator jaws.  If you give it enough space, it will coil around you like an anaconda and crush you to death but even if you manage to find a space too narrow for it to pursue there is still the Behir’s breath weapon, a five-foot wide line of electrical energy that does enough damage to melt weaker adventurers entirely and can put a dent in even the mightiest of heroes.  As a cherry on top of their already deadly arsenal they can just swallow you whole.  Yeah, after they coil you like an snake they can just swallow you like… well… that same snake and then you have to try to cut yourself out.

One last thing worth noting is that Behir’s aren’t just stupid beasts.  They have sentience and are actively evil and malicious, they’re not scholars but they are more cunning and even more charismatic than the average human.  They also have a bonus to stealth, in spite of their massive size, so they could potentially even stalk the party unnoticed.

How to Use Them

The Behir is a monster whose entire lair can be built around a running boss fight that technically starts as soon as the heroes enter the dungeon whether the players realize it or not.  The Behir is the top predator in its domain and so most other creatures that might pose a threat to the heroes have already been eaten.  The good news is that this means that only the Behir needs to be dealt with, the bad news is that the heroes are in its home in territory that is alien to them but that it knows like the back of its hand.  They have to find nooks and crannies to hide in, or spaced to fight from where it cannot effectively constrict and eat them, but of course they can’t stay put for too long because if they do they might fall victim to the Behir’s breath weapon and they also have to avoid letting themselves be cornered.

To maximize this encounter, have the entire cave mapped out with plenty of passages and hiding spots but use visual obstructions on your battle map to keep fog of war up.  Make doubling back a scary experience and keep your heroes guessing about where the big nasty will pop up next.

4. Vargouilles (CR 1, Volo’s Guide to Monsters)

Do you want to see a zombie apocalypse in a D&D game?  Well that’s exactly what vargouilles (pronounced “var-gweels”) can give you.  Fiends from the abyss, vargouilles are basically the pests of the demon world.  Still, what might be a nuisance in the abyss is a menace in the human world and vargouilles are absolutely terrifying.  Sure, an individual vargouille might be easy enough to dispatch.  A capable warrior can make quick work of them.  The problem is that they rarely travel alone and reproduce rapidly.  Even a few vargouilles together can be extremely dangerous, and unlike most creatures in the monster manual the vargouille is even more dangerous outside of a dungeon than inside.

So that’s a lot of flavor text, but how do they work?  Well, for starters the vargouille has a particularly nasty bite that averages out at 15 damage, which is already pretty nasty for their challenge rating.  Odds are, though, they’re not going to start with the biting because they also have their Stunning Shriek, which frightens and stuns creatures within a 30 foot radius.  One the shriek incapacitates someone, the vargouille can apply a “Vargouille’s kiss” which slowly warps the creature, eventually turning them into a vargouille themselves.  This curse happens over time, much like a zombie virus, and is stalled but not cured by exposure to sunlight.  This means that even a small band of these monsters could terrorize an entire city as their numbers slowly grew until eventually it was a full-scale apocalypse.

How to Use Them

Okay, so as cool as a vargouille apocalypse would be I really don’t think that’s the best use of this creature or the coolest apocalypse you could introduce into your campaign, although the looming threat of it should be made very apparent to your players.  Much like the Invisible Stalker, vargouilles are at their best when being used as the catalyst for a larger adventure.  Vargouilles are minions, perhaps controlled by an evil vampire or demonologist who sends them out to terrorize a local populace.  Why?  For science or perhaps out of cruelty, maybe because he knows that their continued harassment of the city will keep those in the population capable of casting a “remove curse” spell busy, effectively eliminating many who would challenge them without having to invest in a more powerful minion.

Vargouilles are a vicious threat in combat, sure, but they also create a mystery for the players to solve and hint at a bigger threat for the players to face.  The impending apocalypse also creates a higher sense of urgency, and the knowledge that one of the players might be subject to a vargouille’s kiss can go a long way in creating suspense during an adventure.  Also, I can tell you from experience, few things put you more on edge than trying to reach safety while waiting for your character’s head to fall off and start flying around.

3. Intellect Devourer (CR 2, Monster Manual)

Beware the brain with legs!  No, seriously, beware the brain with legs you guys.  This entry is technically a violation of the rules I put forward at the beginning of the list because Intellect Devourers are created by and often serve Illithids, but I’m including them because I really feel like “serving the Mind Flayers” is a waste of this creature’s potential.

So let’s talk about what they do.  In melee, the brain with legs has a claw attack that’s kind of meh and even the damage from its “Devour Intellect” attack isn’t particularly devastating.  What IS devastating, though, is how that attack can incapacitate an adventurer in a single round.  Were you hoping that your raging barbarian would smash the monster into a splatter of grey matter?  Too bad, he’s unconscious now because he got his brain shut off and that’s just the start.  An Intellect Devourer also has the ability to eat an incapacitated creature’s brain and take over its body, pod-person style.  When it does this it gains all of the previous creature’s knowledge, including languages, skills, and even spells.

So your barbarian charges, gets zapped, and then gets his body taken over and now you’re fighting your own party member and, even if you beat him, the monster jumps out of his brain and you STILL have to deal with it while it’s trying to get in the brain of one of your other heroes.

How to Use Them

As deadly as they are in a straight up fight (especially if they can weasel their way into some kind of ambush) I feel like Intellect Devourers are best used as mastermind villains.  The devourer getting in the head of one of your adventurers is just the start, but what if they got into the brain of someone with power and authority who was adjacent to the players.  What if a city governor or the king’s chancellor fell victim to one of these?  What about the noble champion or one of the PCs mentors or old friends, whom no one would ever suspect because of their history and reputation?  The creature knows everything that its host had known, and so could put on an excellent deception as it vied for power.

Even though this creature has a challenge rating of 2, with the right setup it could be the villain of an entire arc.  A monster hiding in plain sight as everyone around it, including the heroes, did its bidding and positioned it to take control of a city or perhaps an entire kingdom because no one had ever considered that they might be a pod-person.  Fortunately, the players start discovering the truth bit by bit, little by little, not because the beast gives it away through a bad performance but because they start finding the work they do for the host to be morally questionable or find a piece of evidence that conflicts with the story that they have been fed.  Eventually, they confront the villain and fight him, perhaps knowing the whole truth and perhaps only finding out when the beast ejects itself from his hosts skull and tries to take over a member of the party.

What’s excellent about this is it allows you to reward players for figuring out more of what’s going on.  If they just figure out that the host is behind the villainy then they’re likely in for a bad time, but if they figure out all of the details they can go in prepared and have an infinitely easier time at the end.

2. Catoblepas (CR 5)

The Catoblepas at first glance just kind of looks like a normal animal.  Sure it looks kind of dopey and weird, and it was clearly assembled from spare parts after all of the other creatures of the land were finished, but if you read their description you start to realize how much potential they have as not only exciting encounters but as a flavorful addition to an adventure.

The Catoblepas has an interesting combat arsenal, sure.  Their stench can poison anyone who starts off in melee with them and people who don’t end up poisoned might end up stunned when the creature slams them with its tail and staying at a distance isn’t much safer because of their necrotic eye beams.  Oh yeah, they shoot death rays from their eyes, it’s awesome.

Their potential in combat, though, isn’t nearly as cool as their flavor text.  Catoblepas aren’t just normal monsters who might attack travelers or raid a city, they’re walking figures of death who blight an area just by their presence in it.  Having a catoblepas take up residence near a village creates an automatic threat even if the monster never comes near the people.  They blight the water and wither the crops and fill the air around them with their stench.  Animals who live in their territory become more aggressive, making it even more dangerous to hunt the beast.  You could travel over miles of hostile territory, with every living thing nearby trying to kill you, before you finally found the monster and had a chance to fight it.

How to Use Them

Depending on the level of your players, there’s a lot to be done with a Catoblepas.  For lower level adventurers, the beast itself might be the culmination of the adventure.  Something has taken up residence in the nearby woods, or even near the villages water source, and its blight will make the village uninhabitable and kill everyone if you don’t step up.  Hunting a Catoblepas can be, by itself, a full adventure in the wilderness.  Running an adventure that takes place entirely outdoors is a little strange sometimes, but it can also be a lot of fun.

For a higher-level party, though, the Catoblepas might be merely a symptom or pet to a greater threat.  The creature’s description suggests that sometimes they are kept as pets or even herded by hags, but any particularly wicked and grotesque creature could bring one of these foul creatures with them.  Hags, vampires, even a particularly wicked humanoid could all be responsible for the creature’s presence.  This opens up the door for some great storytelling because the heroes can enter the adventure feeling confident and triumphant (We’ll be fine!  It’s only a CR 5 and we’re like, level 8!) and end up realizing that they may actually be in over their head when they find out that the real threat is much, much greater.

1. The Flail Snail (CR 3, Volo’s Guide to Monsters)

The flail snail is one of those creatures that always seemed to only exist so you could laugh at it’s name and it’s silly face.  “Oh my god, it’s a snail with little maces on its head!  Look at its name!  The FLAAAAAAIL SNAIL!”  Because of that joke, I think a lot of people overlook the value that the flail snail has to be part of an exciting and fun adventure.  Unlike most of the monsters on this list who belong in a nightmare, the flail snail is neither cruel nor predatory.  The flail snail isn’t going to terrorize any villages or put the kingdom at risk.  However, it’s lack of sentience combined with the extremely high value of its shell make it the perfect subject for a fun and exciting subterranean treasure hunt.

The shell of a flail snail is worth 5,000 gold and can be crafted into magical equipment including a Robe of Scintillating colors and spell-reflecting shields.  This means that the flail snail provides a great prize for adventurers to seek out, either on their own or at the behest of a wealthy patron.  Furthermore, while many subterranean adventures are dark and bleak, the brightly colored nature of the flail snail allows you to set a completely different tone altogether.  Imagine cavern halls that glisten and reflect light not only from the ever-present sheen of the flail snail’s glass trails but also from crystalline structures within the rock itself.

Make no mistake, though, the creature is no slouch in combat.  It is a strong resistance to magic, as well as the ability to reflect spells back at the caster or convert magic into a damaging burst of energy.  It has a relatively high AC for its level and can attack up to five times in a round.  They also have their “scintillating colors” attack that allows them to impose disadvantage on their enemies and potentially stun them.  Lastly, when the flail snail’s flails all die off the creature emits a horrible screech for several minutes, meaning that any other creatures in the area will be alerted to the hero’s presence.

How to Use Them

Like the Catoblepas, there are a few ways to build and adventure around the flail snail.  I would highly discourage just having it be an unimportant encounter because, while it’s cool, that would waste a lot of potential.  If the party is lower level, merely hunting the creature could make for an awesome adventure.  Perhaps a nearby city needs the shell for medicinal purposes or maybe they need to craft some of those anti-magic shields.  Maybe the local baron just wants one as a trophy.  Whichever it is, the hunt for the flail snail can take your heroes through all sorts of bright and magical parts of the underground, fighting far more colorful creatures than subterranean adventures usually provide.

But what if the players are too high-level to be challenged by hunting such a creature?  Well, that’s where their death wail comes in.  Maybe the flail snail is in the domain of another civilization, perhaps a city of gnomes or underground fey who treasure the glass-like secretion of the creature for its beauty and perhaps for its own magical properties.  In this case, hunting the flail snail is only the beginning because after they have killed it they have to grab the shell and escape after the enemy is alerted to their presence.  Also, because the shell weighs 250 lbs, at least one of the adventurers is going to be pretty heavily encumbered, making the chase more difficult (and exciting!)

Did I miss your favorite strange creature?  Let me know in the comments here or follow me on Facebook or Twitter to leave a comment there.