10 Scariest D&D Monsters To Use in Your Horror Campaign

The game of Dungeons & Dragons has hundreds of monstrosities, creatures, and curiosities to be found and often fought. In fact, one of the game’s essential tools is called the Monster Manual! But not all monsters in this game are created equally.

While most people think of the game as purely high fantasy, the storytelling potential of this tabletop roleplaying game is only limited by your imagination. Still, rules and supplemental materials exist to help players and Dungeon Masters (or DMs) tailor the experience to their own styles.

In recent years, Wizards of the Coast has introduced a host of new tools for telling tales across the horror, science-fiction, and even mystery genres. For example, Van Richten’s Guide to Ravenloft is an adventure supplement that delves into the Domains of Dread, a series of frightening regions inspired by horror tropes like zombie apocalypses, ancient tombs full of curses, and the plague. Powers of transformation, telepathy, and inducing madness transform fantasy creatures into something quite disturbing.

Adventurers will need plenty of bravery if they’re going to face the dangers that await them in the realms of the mind. Here are 10 of the absolute scariest monsters featured in 5th Edition Dungeons & Dragons.

10. Doppelganger

Trusting your teammates is key to surviving any D&D campaign. But what if it turned out that one of your companions had been secretly replaced by a monstrous lookalike during that last harrowing dungeon escape? Enter: the doppelganger. With a name from the German words for “double” and “walker,” the doppelganger isn’t necessarily an original Dungeons & Dragons creation, but it certainly fits right in with the rest of the Monster Manual. It can polymorph into any small or medium humanoid it has seen before.

When it transforms, a doppelganger doesn’t automatically inherit specifics about the target creature like languages known, mannerisms, memories, or personality. They can, however, use light psychic abilities to gather surface thoughts and will often tail the person they intend to replace — sometimes going so far as to kidnap them and study them before assuming their form.

Occasionally, players will secretly coordinate with their Dungeon Masters to have their characters replaced by a doppelganger mid-game, unbeknownst to their allies. This deception adds incredible plot-twist potential as well as plenty of paranoia to a table.

9. Boneless

Adventurers are no strangers to fighting off hordes of skeletons, zombies, and other undead monstrosities. What they might not be familiar with, though, is encountering the boneless. This horrific entity is devoid of a skeleton, leaving a shambling, wavering mass of corpse skin. They can arise through dark sorcery or necromancy and are absolutely, 100%, an affront to the good name of the undead.

Not only is this nightmare fuel able to contort and compress into tight spaces and slip under doorframes, but the boneless is driven by a desire to wrap a living frame in its crushing embrace. Yeah — no free hugs. However, it’s not uncommon to see a boneless wrapped around other forms of undead, such as a skeleton. It can separate from the form carrying it and attack independently, making a two-for-one jumpscare for players.

Additionally, it doesn’t need air, water, food, or sleep — and after encountering one of these on your quest, you might not ever sleep again either. It’s enough to make your skin crawl (even after death).

8. Mind Flayer

Fans of Stranger Things might be familiar with the name Mind Flayer, and while the tentacled smoke monster from the Upside-Down shares some loose similarities with the D&D monster (like implanting evil tadpoles in its victims), these Forgotten Realms inhabitants might be even scarier than what’s in Hawkins, Indiana.

Also known as illithids, these eldritch creatures are excessively powerful psychics, ruthless scientists, and sadistic aberrations that lurk in the Underdark. Unlike many mindless, lesser monsters, the mind flayers are cunning and use their psionic abilities to subjugate other races. They also quite literally eat brains and devour personalities and memories from their captives.

Surrounding their hivemind society with cerebral beasts like intellect devourers and elder brains, the illithids are not so easily defeated by the power of friendship — sorry, Will the Wise.

7. Gibbering Mouther

Gibbering mouthers are as awful as they sound (literally), usually the result of foul magic and complete madness. As the name and form suggests, this creature is an amorphous mass of mouths, eyes, and ooze that actually is the liquified matter of countless victims. Its constant chattering, crying, and screeching is a result of all the minds contained within going insane at the destruction of their bodies.

If that wasn’t charming enough, the way the gibbering mouther moves is by latching several of its mouths onto the next destination point and pulling its oozing form across the ground. It can also swim or move through viscous substances like mud and quicksand. This aberration only seeks to consume. It hunts and devours living flesh — at which point, the latest victim’s eyes and mouth will erupt from the surface of the creature and join the chorus of noise.

6. Mimic

Even when facing down the most terrifying of foes, it helps when you know what you’re up against. When your heroes encounter a Red Wizard of Thay chanting evil rituals, it’s easy to launch a coordinated attack. But the line between good and evil isn’t always so black and white. Mimics exist purely to terrify players into never trusting anything. Ever.

Famously taking the form of treasure chests to surprise greedy adventurers, mimics are shape-changing monstrosities that are indistinguishable from mundane objects when dormant. They have an adhesive quality and many, many teeth, meaning anyone who touches one is likely to get grappled and bitten. Creative (read: evil) Dungeon Masters like to vary the forms their mimics can take — doors, chairs, floors, coffins, or just about anything else the players might encounter without a second thought. Soon enough, you’re going to see teeth everywhere!

5. Oblex

As we saw with the gibbering mouther, it’s generally never a good sign when a creature or construct is covered in faces. Well, thanks to the sadistic experimentation of the mind flayers, we have oblexes. The oblex is a wickedly intelligent sentient ooze that undulates with the memories and echoes of its former victims, which have been consumed and assimilated into its monstrous form.

Oblexes can make copies of their consumed prey that are capable of moving up to 120 feet away from the creature’s primary mass, though the copies cannot separate completely and are tethered by a thin trail of slime. While they have a sulfuric smell to them, these near-perfect duplicates (not to be confused with the doppelganger described above) contain the memories and mannerisms of their former selves. This uncanny ability is used as a predatory tactic, luring away more victims to feast upon.

To prevent overwhelming madness, oversaturated oblexes split into smaller masses, continuing to feed from there. Bon appetit!

4. Aboleth

While the aboleth is not quite the biggest or strongest thing living under the sea (not when there are krakens in the Forgotten Realms), its unique abilities provide both a physical and mental challenge for adventuring parties. Paired with the fact that it’s usually only encountered on the open seas or in deep, dark lake waters, this primordial menace can quickly send heroes to sleep with the fishes.

Before the gods, aboleths lurked in the abyss. They now bide their time until they can overthrow the gods, otherwise ensnaring and enslaving adventurers in their briny lairs. Not only can aboleths psychically probe heroes and learn their greatest desires and influence them with visions, but they have a multitude of mucus-ridden tentacle attacks that can inflict disease on creatures. This mucus forces the afflicted to lose the ability to breathe above water or take acid damage if they are not presently in a body of water.

Between the aboleth’s telepathy, ability to alter another creature’s physiology, and ability to influence water to channel its rage, its entire action economy is designed to trap players, earn or force their loyalty, and eventually obliterate a person’s sense of reality. We’ll take the toothy treasure chests any day.

3. Sibriex

As if regular demons weren’t bad enough, sibriexes are huge, warped demons that ooze corrupting blood and bile wherever they float. They constantly smell of rotted vegetation, and their underbellies are a mass of tentacles, stalks, and feeding tubes. Sibriexes often use animated chains as their primary form of locomotion to navigate their bloated forms through the hellish planes.

Their influence is both physically and psychically corrupting, confusing the minds of those who encounter and approach the demon. Sibriexes, like mind flayers, are intelligent and perform perverse experiments on lesser beings — in fact, these creatures are known to bully and torture inferior entities. Where illithids preoccupied themselves with the brain, these demons engaged in the practice of grafting flesh, seeking to create the perfect creature construct.

The abominable results of their poisonous powers create abyssal wretches, which can only be undone by a wish spell. They can quickly create armies of charmed, grotesque demons who view their sibriex master as the ultimate life form.

2. Star Spawn Emissary

While D&D is largely a high fantasy game, alien influences can be found throughout extended worldbuilding materials. The settings of the Domains of Dread introduced the region Bluetspur, a place steeped in cosmic and eldritch horror. Dominated by the God-Brain, this is just one example of the astral influence of outer planes. Star spawn emissaries are another example of this terror, presented as invaders from the multiverse that are nearly as incomprehensible as they are devastating.

The emissary has two forms — lesser and greater. The lesser form allows it to appear as any creature, such as an animal, person, or other unassuming entity. It attempts to hide among the inhabitants of the current reality, but when revealed, it shows its true nature as a mass of “agitated organs, self-cannibalizing orifices, and appendages suggestive of forms it has previously assumed.” (Think John Carpenter’s The Thing.) Its greater form, however, is even worse. Openly mocking the feeble minds of the reality it currently inhabits, it appears as a 25-foot-tall pillar of flesh and voices mimicking every other form it has ever taken.

Its psychic powers alone are enough to break even adventurers of the strongest resolve, but the unearthly physical forms it can inhabit are malleable and sanity-shattering. It is incredibly difficult to defend against in any of its ever-changing states.

1. The Bagman

Introduced to 5th Edition Dungeons & Dragons by way of Van Richten’s Guide to Ravenloft, the Bagman is listed as more of an urban legend than a monster manual entry. While this entity doesn’t come with specific stats, there is plenty of lore surrounding the figure (who functions like modern myth monsters such as Slenderman or various SCPs). But what might be scariest of all is that the Bagman inhabits one of the most common, most necessary magical items for any adventuring party — the bag of holding.

The Bagman is said to be an adventurer who abandoned his own party in the height of battle and hid within a bag of holding, which isn’t designed to sustain living creatures for very long. He became lost in the extradimensional spaces within the bag while trying to escape, slowly transformed into a monster by the immense magic of the object. Now, the Bagman slips out from one random bag of holding each night, still searching for his way home. If he cannot find it, he drags one helpless victim into the bag with him and leaves a random item as a trinket in their place.

Secure the Bag

What makes this scariest of all is that it’s up to the Dungeon Master whether or not the creature is real. Without a definite stat block, he could simply be an effective storytelling tool for players. Nearly everyone has a bag of holding, entrusting it with money, magical items, and more. But every character needs sleep, or at least some form of rest. Should paranoid characters keep their valuables close and risk being the Bagman’s nearest target? Is he just a harmless tale from the Domains of Dread?

Adventurers who want to test the legend for themselves can speak into their own bag of holding and say, “Follow my voice” three times to possibly summon the Bagman. Would you dare to discover the truth of this horrible legend?

Hey, not every adventure can be slaying kobolds and collecting riches! These are just a few of the frightening foes that can be found in the game — Dungeon Masters can make just about anything scary in the right context.

Did we miss any of your favorite nightmare-inducing monsters? Keep the conversation going in our Let Your Geek Sideshow Facebook group at side.show/geekgroup!

There’s a chill in the air. The leaves tremble in a skeleton dance and shadows seem a shade darker. Channel the spirits and revel in Sideshow’s Spooktacular 2022 — a celebration of all things sinister, scary, and downright spooky.

Join us from October 24 – October 31 by visiting side.show/spooktacular and don’t forget — Sleep is for the weak!