You struggle to break free from the tight grip of the mind flayer’s tentacles. Helpless it drags you to its mouth. The last thing you feel is a sharp pain biting into the back of your skull. You hear a loud crack. Then there’s only darkness…
It’s wild that I haven’t done a Monster Monday on mind flayers before considering that the creature was the first permadeath of my most recent campaign. These are nasty creatures even if you aren’t using the spellcasting variant. Case in point, they have an execute as a CR 7 creature!
They’re my go-to creature choice when I want to make things weird in a campaign too. Case in point, the mind flayer I used in my previous campaign was the guardian of the entrance to a wacky pocket dimension full of vampiric myconids.
As I’ve said before, I’m by no means a stickler for the D&D/Forgotten Realms lore. I throw it away more often than I use it. Though it is useful for getting a general vibe of how creatures might act.
Mind the tentacles as we make our way into the Monster Manual to learn all about the psionic terror, the mind flayer.
Mind Flayer Lore
Let’s get this out of the way immediately. Mind flayers, also known as illithids, are evil. They were also once the rulers of empires that spanned many different worlds a long, long time ago.
While they’ve since had a devastating (and deserved) fall from grace, they obtained this great power from their mastery of psionics. They would use their psionic powers to subjugate and enslave countless races of humanoids, most of which still suffer the impact that this had on their ancestors.
Since the fall of their empire, illithids have been shamed into living in the corners and crevices of the Underdark. Here they still prey on and enslave creatures using mind control, but they do not have the terrifying power and numbers that they did in eons past.
Mind flayers also use their psionics to create an insect-like hivemind. They talk to each other through telepathy and colonies are run by an elder brain that works as the literal brain of the colony.
As the name implies the mind flayer has some type of attachment to the human mind or brain. This is because mind flayers need to consume the brains of humanoids to survive. When consuming a brain the illithid will gain all the nutrients they need to survive while also learning all of that person’s memories, fears, and personality.
Mind Flayer Stats and Abilities
You can find the mind flayer’s statblock on page 222 of the Monster Manual.
Size: Medium abberation
AC: 15 (breastplate)
HP: 71 (13d8 + 13)
Speed: 30 ft.
STR: 11 (+0)
DEX: 12 (+1)
CON: 12 (+1)
INT: 19 (+4)
WIS: 17 (+3)
CHA: 17 (+3)
The mind flayer is a textbook glass cannon. They have a high damage potential, but that comes with the price of having super weak defenses.
Case in point, their low AC and HP due to their mediocre Dexterity and Constitution. One of these ability scores being low is tolerable, but having both makes not only the creature weak to attacks and damage but also most saving throws.
The mind flayer needs to go all-in on their offenses to ensure their survival. Thankfully this is doable due to their vast amount of crowd control which requires Intelligence saving throws. Making their chances of distributing said crowd control quite favorable.
Their high Intelligence is also a boon as it is used for their attacks as well.
All in all, the mind flayer’s base stats are much to be desired. They’re not well-rounded by any stretch of the imagination.
Resistances, Immunities, Saves, and Skills
Saving Throws: INT +7, WIS +6, CHA +6
Skills: Arcana +7, Deception +6, Insight +6, Perception +6, Persuasion +6, Stealth +4
Senses: darkvision 120 ft., passive Perception 16
Languages: Deep Speech, Undercommon, telepathy 120 ft.
CR: 7 (2,900 XP)
It’s unlikely that a mind flayer will fail any type of Wisdom saving throw thanks to both their proficiency in it and Magic Resistance. Proficiency in Intelligence and Charisma saving throws are nice perks but they’re nowhere near as common as Wisdom saving throws.
Mind flayers are more than just a generic creature to throw in a dungeon. They are intelligent creatures with tons of out-of-combat skills. While they’re skilled in combat, the mind flayer may opt to use their silver tongue and intellect to talk their way out of a scuffle with the party.
Their stealth is also a nice perk and could give them a leg-up on the party if they can hide and gain a surprise round.
Due to the destruction of their civilization, illithids are now found hiding deep within the Underdark. It should come as no surprise that they have exceptional darkvision. Their high Wisdom also gives the fantastic passive Perception making it difficult for them to be ambushed.
Telepathy is a fun toy to have when playing a mind flayer. Use its generous range to mess with the party as they traverse the dark cave system or dungeon. Use intimidation and deception to make the party think twice about drawing their swords when you meet them face-to-face.
I think CR 7 is fair. They’re a tough creature to judge due to their plentiful utility not translating into something quantifiable in a CR calculation. Their damage output also has a high variance. A mind flayer could demolish a party easily if they can quickly incapacitate them. However, if the party resists the mind flayer’s abilities they’ll be able to quickly chop it down without much of an issue.
Traits and Abilities
Innate Spellcasting (Psionics).The mind flayer’s innate spellcasting ability is Intelligence (spell save DC 15). It can innately cast the following spells, requiring no components:
Magic Resistance. The mind flayer has advantage on saving throws against spells and other magical effects.
While there are variant versions of the mind flayer that include a more robust spell list the base mind flayer has some goodies as well. Detect Thoughts is a solid spell for social interactions. The mind flayer can leverage it to determine the party’s intentions and feelings if they have a parlay rather than a fight to the death.
Levitate can be used defensively to avoid melee attacks or it can be used to crowd control an enemy. This coupled with their other forms of crowd control makes the mind flayer a fantastic support unit in combat. Pair them up with some heavy-hitters and they’ll be an absolute terror to face.
Dominate Monster is just a powerful spell to use on the party’s melee attackers. If it connects it will give the mind flayer a frontline unit to throw at the party while it continues to subdue them with crowd control.
Oh and Plane Shift is nice when you need to get the hell out of danger real quick.
Magic Resistance is one of the few defensive bright spots of the mind flayer’s statblock aside from their saving throw proficiencies. It’s quite unlikely that they’ll wind up failing any WIS, INT, or CHA saves and this does give them a much-needed boost for their CON and DEX saving throws.
Tentacles. Melee Weapon Attack: +7 to hit, reach 5 ft., one creature. Hit: 15 (2d10 + 4) psychic damage. If the target is Medium or smaller, it is grappled (escape DC 15) and must succeed on a DC 15 Intelligence saving throw or be stunned until this grapple ends.
Extract Brain. Melee Weapon Attack: +7 to hit, reach 5 ft., one incapacitated humanoid grappled by the mind flayer. Hit: The target takes 55 (10d10) piercing damage. If this damage reduces the target to 0 hit points, the mind flayer kills the target by extracting and devouring its brain.
Mind Blast (Recharge 5–6). The mind flayer magically emits psychic energy in a 60-foot cone. Each creature in that area must succeed on a DC 15 Intelligence saving throw or take 22 (4d8 + 4) psychic damage and be stunned for 1 minute. A creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.
The mind flayer’s action economy is horrid. It can only make a single attack per round. However, each of their attacks is quite powerful.
For starters, their bread-and-butter Tentacles includes damage and a grapple with a high chance of stunning the target for the duration of the grapple. That’s a ton of value packed into one action.
Extract Brain is the source of most of the mind flayer’s damage output dealing an average of 55 damage per action. The catch is that this attack can only be used on incapacitated targets. Ergo, a target must be stunned by either Tentacles or Mind Blast before it’s usable.
It also has the benefit of including an execution. If the target is brought to 0 HP they are flat-out killed. They do not get to make death saves.
Last but not least we have Mind Blast which is a rechargeable action. It includes a respectable amount of damage, but its wide range and Intelligence saving throw are what give the action its power. This should be used asap to set up Extract Brain and lessen the party’s damage output.
Despite having only a single action per turn the mind flayer has a ton of fantastic options between their action list and their spell list. They boast a ton of great utility and some potentially lethal damage.
Mind Flayer Strengths
Phenomenal Crowd Control
The mind flayer has tons of crowd control packed into their kit. Like an ungodly amount.
For starters, they can cast Levitate at-will to mess with a melee attacker. They also have a single cast of Dominate Monster each day. Both of these are solid options that also require concentration.
Then they have their actions. Two of which have a chance of stunning their targets. Mind Blast is an AoE stun. Tentacles is a basic attack that has both a grapple and a chance of stunning making it a valuable crowd control maneuver.
Keep in mind too that both of these actions’ crowd control requires an Intelligence save. This is quite powerful because Intelligence is such a common dump stat in D&D 5e. It’s more than likely that these actions’ crowd control will be potent.
Massive Potential Damage
Tentacles is a very mediocre attack action concerning its damage. It’s the creature’s go-to simply because you need it as a setup maneuver should your Mind Blast fail to connect.
Extract Brain is where almost all of the mind flayer’s damage resides. That 10d10 damage is an absurdly dangerous amount of piercing damage. Especially since it’s almost guaranteed to hit thanks to having advantage on its attack roll due to the creature being Stunned by either Tentacles or Mind Blast.
Also tack-on the execution portion of Extract Brain and the mind flayer can be a lethal opponent and has a solid chance of pulling off a TPK.
Mind Flayer Weaknesses
The mind flayer is both a terrifying and deadly foe and a vulnerable one at the same time. They heavily rely on their crowd control abilities for both their damage and their survivability.
If the party is overall decent at making Intelligence saving throws the mind flayer may not be a big threat. For example, a party with access to the paladin’s Aura of Protection has an enormous leg-up on the mind flayer’s saving throws.
That said, this risk does at least come with plenty of rewards. Should the mind flayer be able to stun a sizeable chunk of the party they become a terrifying threat. Yet this drawback is still something to keep in mind when you are planning an encounter with a mind flayer.
Weak Physical Defenses
While Magic Resistance and their saving throw proficiencies give the mind flayer a solid chance to beat most saving throws against magic, the mind flayer still has abysmal defenses.
Their AC even with armor is only 15. Couple that with below-average HP and you have a creature that’s susceptible to direct attacks. If their crowd control fails them the party’s attackers will beat them to a pulp.
Coupling the mind flayer with some frontline units (or stealing one from the party with Dominate Monster) will help alleviate this issue. It’s both thematic and it gives the mind flayer some time to set up their crowd control for Extract Brain.
How to Play a Mind Flayer
Lurk in the Shadows and Strike
Whether or not your mind flayer has some minions they can still use their proficiency in Stealth to their advantage. There should be plenty of dark nooks and crannies in the Underdark for the mind flayer to hide in wait for the party. If they’re successful they can use the element of surprise to unleash Mind Blast or Dominate Monster to set themselves up for success.
Their weak defenses mean that you need to be careful with their positioning. They are not tanky creatures. They need to use trickery and pawns to ensure their survival. If they’re able to dish-out their crowd control the battle is theirs to win, but they need time to do that.
A mind flayer may also use underlings as bait. For instance, they might have a quaggoth or two sit in the middle of the room while they hide. The party will engage the quaggoth and when the timing is right the mind flayer can reveal themselves and use Mind Blast.
Sure this will seal the quaggoth’s fate, but let me remind you that mind flayers are evil bastards. They don’t care what happens to their underlings.
A Proper Set-Up Makesfor an Easy Clean-Up
The mind flayer’s weaknesses and diverse kit make for an interesting playstyle that requires you to diligent in your early-game setup.
Depending on the circumstances you’ll want to either use Mind Blast to stun multiple enemies or use Dominate Monster to build up the mind flayer’s frontline defenses. From there you’ll want to use Tentacles to stun any outliers or Extract Brain to begin dealing massive damage to your enemies.
Use Mind Blast when it is available to subdue the remaining enemies and then clean up with Extract Brain should you have everyone stunned.
Your goal isn’t to dish-out massive damage. It’s to crowd control your enemies then destroy them. Think of playing a mind flayer like how a spider hunts. You want to entrap your prey and when they can’t move you suck out their guts!
5 Mind Flayer Plot Hooks
- Hidden Treasure: A labyrinth deep within the Underdark is said to contain a legendary dagger whose craftsmanship is unmatched. Various adventurers have tried, but failed to breach the inner sanctum of this dungeon that’s said to be chock-full of otherworldly guardians.
- Break Their Psionic Hold: Stories of the illithid’s treacherous reign eons ago are well-known. It’s said that a colony of mind flayers has begun to lay the foundation of such an empire using humanoids in the Underdark.
- Strange Adventurers: A group of strage folk claiming to hail from another plane of existence are here to search for “the illithid menace”. What could they mean and should you help these people?
- Awww it’s so… cute?: A four-legged brainlike creature was found scurrying around the market. No one knows what it is, but it might be some wizard’s weird pet or familiar. I’m sure someone will be looking for it!
- Recover the Brains: A mind flayer has a workshop deep within the halls of a nearby dungeon. It’s said that the mind flayer extracts brains of wandering humanoids not for sustenance but to use for their sick and twisted experiments in their workshop.
Mind flayers are overall solid creatures. They have a few noticeable weak points but also bring a ridiculous amount of crowd control and utility to the table while still dealing respectable damage. Concerning combat, they’re a formidable foe.
Their lore is both disturbing and interesting which for a creature of the Underdark is par for the course. They are hated by many different humanoid races for a laundry list of valid reasons. Ergo they make for some fantastic villains for your party to thwart.
All in all, they’re one of my favorite classic D&D creatures. I love having an excuse to throw one into my games since they exploit some of the common weak points that the 5e character-building meta leans into. For example, using Intelligence as a dump stat.
If you’re looking for a creepy and irredeemable aberration for an adventure the mind flayer is the choice for you!