One of the most effective ways to deal with an enemy is to rob them of their greatest weapon - their mind. This trope is a subtrope of Mind Rape, an intentional attack on someone's intellect. In layman's terms, deliberately making someone stupid.
This trope can take many forms. It can be temporary or permanent. It can be achieved through magic, surgery, head concussion, or weaponised Phlebotinum-Induced Stupidity. It can have any number of degrees of severity, ranging from simply taking the edge off the victim's reasoning to full-on infantilisation or even reducing them to a drooling vegetable. Finally, depending on the work's tone, it can either be Played for Laughs or be a potent source of Nightmare Fuel.
This attack also has a variety of uses. It can be a means of control, a way to neutralise a troublesome Guile Hero or Chessmaster, or even a particularly sadistic torture method or Fate Worse than Death (especially if the victim's aware of what's happening to them). Some characters, in fact, use it to boost their own knowledge and intellect via a form of Vampiric Draining, though this is not strictly necessary to the trope. Whatever the case, though, removing some IQ points from the target must be a deliberate purpose of the attack, not just a side-effect.
Contrast Idiot Ball and Took a Level in Dumbass, where it's the writer dumbing down their characters. Compare Phlebotinum-Induced Stupidity, which is often unintentional and possibly either self-inflicted or the result of some environmental effect, as well as Brought Down to Normal or Depower, an event with a similar purpose used to strip away someone's physical or supernatural abilities. Not to be confused with Brain Drain, which is about making a company or organization dumber by stealing away talented employees.
- In Mobile Suit Victory Gundam, the Angel Halo is designed to fire a permanent Stupidity Inducing Attack at the population of Earth. Definitely not Played for Laughs, as the stated intention is to fire it, and then sit back and watch as the entire population starves to death due to being unable to feed themselves.
- Bobobo-bo Bo-bobo:
- During the fight with Pana of Giga's Six Cyber Knights, Poppa Rocks/Don Patch summons a literal idiot ball in retaliation against Pana's Psycho Balls. However, all it actually does is make you ace an upcoming test... by CHEATING!
- Later on against Poet, he stabs a spike into Poet which injects the latter with a fluid that makes Poet think just like Poppa Rocks, and given how Poppa Rocks (Hell, just about any of the fighter on the good side) thinks, this doesn't really go well for Poet in regards to his techniques.
- Kaminari of My Hero Academia can potentially inflict this on himself if he unleashes too much of his electrical power in one shot.
- The Stand "Jail House Lock" from JoJo's Bizarre Adventure: Stone Ocean reconstructs this trope; while active, its victims can only remember three things at a time.
- Parodied in One Piece when Luffy does "Gomu Gomu no Boh/Gum Gum Space Out" and completely clears his mind of thought so Eneru can't read his moves with his Mantra. It's not much of an "attack" as he can't fight back with it.
- Doraemon features the Timed Stupidity Bomb, a clock-like explosive which causes anyone to act like a moron for a brief amount of time.
- DC Comics likes this trope:
- This is used to explain the Villain Decay of Batman villain KGBeast. Originally depicted as a foe so daunting that Batman had no choice but to cross the Godzilla Threshold and break his Thou Shalt Not Kill rule to deal with him, later stories walked this back by showing that he had survived but taken a massive competence dip, to the point that Huntress and Robin could now take him out with little trouble. Later still it was postulated that while he didn't die in his origin story, KGBeast did suffer brain damage from all that time he spent locked in an airless room.
- One of the main subplots of Identity Crisis (2004) revealed that certain members of the Justice League frequently used Zatanna to mind wipe villains if they ever found out things like their secret identities (or in the main story's case, to prevent Dr. Light from trying to rape the Elongated Man's wife again).
- A one-shot prequel to Justice League: Cry for Justice reveals that technically the villain Prometheus was subject to this trope; recognising that it would be impossible to contain the villain in conventional prisons given Prometheus's status as the Anti-Batman, Batman and J'onn J'onzz arrange to trap Prometheus by reducing him to a mentally disabled state, which he only escapes after Final Crisis when J'onzz is killed.
- In the Dragon's Lair comics, Singe kidnaps Princess Daphne and puts her in the Bubble of Helotry, a magical orb that slowly saps the prisoner's intelligence until they turn into a giggling bimbo. Singe had previously used it on the rest of his harem. When Dirk destroys the orb, Daphne and the rest of the girls go back to normal.
- In Fall of the Hulks, the Intelligencia does it on two different levels: with a "neural anesthetizer" of their invention, they dumb down and imprison the smartest of their enemies - Reed Richards, Hank Pym, T'Challa, Bruce Banner and Doctor Doom - effectively lobotomizing opposition.
- Judge Dredd once included a device called the "Stupid Gun" designed to do this. Predictably, it fell into precisely the wrong hands.
- One Super Mario Bros. story from Valiant Comics involved a new weapon from King Koopa- the Stoopid Bomb, a hair-trigger explosive that can make anyone (Except for King Toadstool, who was already a moron) mind-numbingly dumb. There's also the Smart Bomb developed to counter the Stoopid Bomb's effects, though they all get used up on one Snifit. By the end of the story, everyone, including Koopa's army, are rendered idiots, and the now-genius snifit's attempts to take over are ignored.
- In one of the earliest issues of Uncanny X-Men, team leader Professor X does this to teleporting villain the Vanisher, obliterating his competence and reducing him to a Dirty Coward.
- Calvin and Hobbes: During Show And Tell, Calvin claims to have invented one of these- and it's invisible too.
Calvin: I have in my hand an invisible cretinizer! One shot renders the victim a babbling simp, a dolt, an utter moron!
Ronald: OH SURE, CALVIN! GIVE US A BREAK!
Calvin: As Ronald proves, it's quite effective even at long range.
- The Action Prologue of Zim the Slime had this as the Irkens' plan against the brutal Resisty movement led by Dib. By switching the USB stick containing a virus that would destroy the Irken Control Brains, they updated all their forces to be immune to the trump card of GIR hooked up to a machine that would assault everyone in its range with pure stupidity. The Resisty ships start falling out of the sky, shooting in random directions (and hitting each other), with the entire attack on Irken failed in less than a minute.
- Megamind: When Megamind visits the monument to Metro Man, he reminisces about old times and brings up an "Illiteracy Ray", a rather specific variant on this trope.
- In 2001: A Space Odyssey, Dave Bowman pulls a lethal version on the rogue computer HAL 9000, removing its memory modules until its "brain" shuts down. Despite the machine being a clear antagonist, the sequence is remarkably upsetting.
HAL: Dave. My mind is going. I can feel it. I can feel it. My mind is going. There is no question about it. I can feel it. I can feel it. I can feel it. I'm a...fraid. Good afternoon, gentlemen. I am a HAL 9000 computer...
- In Super Mario Bros. (1993), Koopa uses a machine to de-evolve his opposition into mindless Goombas or monkeys, later upgrading to handheld versions.
- In The Adventures of Rocky & Bullwinkle, the villains plan to release Really Bad Television, a series of TV shows so horrible that anybody who watches them becomes a mindless idiot. As per usual (see the regular series below) Bulwinkle is unaffected.
- John Coffey does this to Percy Wetmore in The Green Mile, not through evil intentions but to remove the threat to his friends, resulting in the guard ending up in an insane asylum. It says a lot that Coffey only does this to people he considers to be pure evil.
- The Dresden Files:
- Used by Lara Raith on her father, turning him into little more than a weak-willed puppet for her to control from behind the throne. To be fair, though, the victim in that case really deserved it: He had repeatedly raped his own children.
- Also, whilst all cases so far of it doing this are accidental, mind magic has considerable potential to be used in this way. This is because (a) mind mages tend to rapidly devolve into insane, amoral monsters with little regard for the people they control, and (b) mind magic inflicts permanent brain damage on its victims. Even when Molly first uses it with the best of intentions, the fact that she has baggage with the person she uses it on leads to deeply ingrained paranoid delusions that could end up being permanent.
- In The Wheel of Time, several characters have realized that warping the World of Dreams to make their opponents stupid can be a disturbingly effective attack. When Mesaana attempted to use this against Egwene, her defense was so strong that it broke the Forsaken's mind, reducing her to an infantile mental state.
- Used as a main plot point of an entire arc in Perry Rhodan, when extragalactic invaders did this to the entire Milky Way Galaxy. Some rare few people were immune (including most of the protagonists), but civilization basically broke down right then and there because those few were usually too busy trying to keep all the morons in check and from accidentally killing themselves and each other to keep things running on the necessary scale, let alone go after the actual threat; the need to figure out what was going on and find a countermeasure drove much of the early plot. (The scale of the event was later explained that the so-called 'Cosmic Swarms' were created by Sufficiently Advanced Aliens with the intent to help spread intelligence on a cosmic scale. This particular one had simply been hijacked by ambitious underlings who decided to Reverse Polarity...)
- This is an ability of the Oversoul, the millions old AI that monitors humanity in Orson Scott Card's Homecoming Saga. To prevent humanity from developing to a point where it can potentially wipe itself out, the Oversoul can make those who delve into forbidden ideas suddenly stupid or forgetful until they move on to something else. It takes a lot of willpower for a human being to overcome this. This ability is so powerful that at one point the Oversoul does it to itself.
- Isaac Asimov's Pebble in the Sky: Discussed when the villain threatens to Reverse Polarity on the "synapsifier", an intelligence-boosting machine, causing it to reduce the heroes to vegetables.
- In the Song of the Lioness books, Duke Roger put magical dolls of various people who might suspect him under a veil to make them unable to really suspect him - as soon as they intended to do something or seriously investigate, their resolve would fail.
- Ted Chiang's Understand is about a man who's given Super-Intelligence by an experimental cure for brain damage. In case he ever needs to defend himself from another superintelligent person, he devises a technique to revert enhanced minds to normal. When he actually uses it, though, his adversary invents a countermeasure on the fly.
- Illegal Aliens features a variation with the Stop That Cannon, which fires a powerful psychic command to STOP THAT! at its target(s).
- The Worm in Shadows of the Apt induces this effect. Its minions (who are themselves near-mindless puppets of the Worm's will) carry an aura of ignorance with them at all times, and anyone who gets too close will be stripped of all advanced mechanical and/or magical knowledge. This turns out to be because the Worm itself is little more than an incarnation of primordial hunger — it doesn't understand advanced concepts, but its will is so strong that it can force its ignorance on others.
- In the Uglies series, when you are made into a Pretty at age sixteen, they make you into a bubblehead that won't try and rebel against the entire ideal.
- Codex of Worm has the power to inflict permanent brain damage and memory loss, and gains a temporary boost to her own mental faculties whenever she does so.
- "Without A Thought" (the very first of Fred Saberhagen's Berserker series) features a "mind weapon", which affects not only people but also computers:
Hard experience had taught men something about the berserkers' mind weapon, although its principles of operation were still unknown. It was slow in its onslaught, and its effects could not be steadily maintained for more than about two hours, after which a berserker was evidently forced to turn it off for an equal time. But while in effect, it robbed any human or electronic brain of the ability to plan or to predict—and left it unconscious of its own incapacity.
- In Paula Volsky's The Sorcerer's Lady, the great sorcerer, Lord Terrs Val Grizhni, is finally defeated by his archenemy. The archenemy, enjoying what he thinks is his moment of triumph, opens a casket belonging to Grizhni, which releases a spell that results in him being brain-damaged, terrified, and unable to speak, for the rest of his life.
- In The Amtrak Wars, Mr Snow does this to the commander of a wagon-train so he makes a tactical error by driving it into a gully where it can be ambushed. After the attack starts, he also finds it difficult to think his way out of the situation.
- The Invincible: The "clouds" are a Microbot Swarm which can emit an electromagnetic attack that destroys the higher brain functions of animals, as well as computer-controlled machines. A human that survives the attack must be taught even the most basic things from scratch again and may not even be the same person anymore.
- Topher does this to the head of Rossum Corp. in the finale, using the magic mind-wipey gun to give the villain Active architecture and turn him into a doll against his will. Hell, he's doing this pretty much in every episode, in some form or another.
- Also, the Bad Future shown in the two Epitaph episodes is the result of this being done on a massive scale. By "massive scale", we mean somewhere around 80-90% of the world's population having their minds wiped in a single instant and then being reprogrammed to hunt down and murder anybody that wasn't wiped.
- In Buffy the Vampire Slayer, Glory has a terrifying version of this, where she basically jams her fingers into the sides of the victims head, robbing them of their sanity and intelligence and leaving them babbling and helpless. This happens to Tara, who ends up being the only one cured thanks to Willow. A side-effect of this also benefits Glory as they see Dawn in her true form, which is described as a beautiful, pure green light, and Tara accidentally helps Glory learn Dawn is the MacGuffin because she didn't understand that vocalizing this will result in everyone dying.
- In Get Smart episode "KAOS in CONTROL", the infiltrator stole and used the Electro Retrogressor Gun, a gadget that reduced the victim to the mind of an eight-year-old child.
- In Doom Patrol (2019), the scants are organisms that infect people's brains and cause them to have bad ideas. Under their influence Larry tries to disguise himself as a doctor by putting on a lab coat despite having radiation-blocking bandages totally encasing his head at all times, and Vic and Roni agree it's a great idea for him to do extensive surgery on her even though he has zero experience.
- Sorcery! have an "Insanity Spell" wizards can use to turn their enemies into lumbering idiots, make them believe they're animals and induce idiocy removing whatever threat they may pose. The spell is quite effective, too, with most affected victims unable to fight back allowing the player to defeat them instantly, although some more powerful enemies (like a Deathwraith) might recover after being hit a few times too many.
- Dungeons & Dragons:
- Basic D&D Immortals can perform Ability Score attacks against an opponent's Intelligence.
- The Feeblemind spell takes this straight into And I Must Scream territory. If a target is hit with the spell and fails the saving throw, both their Intelligence and Charisma scores are reduced to 1. They can't talk, can't cast magic, and can't understand spoken language. The only sapient quality they retain is the ability to recognize allies and defend themselves from attack; otherwise, they're basically a feral animal. On top of that, if they aren't healed by outside magic, they can only attempt to repeat this saving throw once a month - which is going to be extremely hard given that the Intelligence save they have to make is done with a -5 penalty due to having Intelligence 1.
- Psionic attacks, from Original D&D (Eldritch Wizardry) to AD&D1.
- The spell ray of idiocy, which reduces the target's Intelligence by 1d4+1, can be hilariously broken if you know how to use it. How? Well, having a 0 in any stat is debilitating; 0 Intelligence causes a coma. Now, all animals have Intelligence 2 or less, and many magical beasts aren't much brighter. Thus, this spell can one-shot anything from a housecat to the Tarrasque.
- The burbling of a jabberwock can confuse other creatures, causing them to stand in place, wander at random, or attack a nearby creature regardless of whether it's friend or foe.
- Magic: The Gathering has Nemesis of Reason whose attack causes you to discard 1/6 of your deck, representative of your mind/knowledge/power. And more generally, this is the idea behind the alternate win condition of "milling." (usually associated with blue mana, which represents mental magic, among other things). When you have no more cards in your deck, you lose. This path to victory is represented by such wonderful spells as Mind Funeral.
- Champions. The Drain power (and in older editions, Destruction and Transfer) can be used to lower another character's Intelligence, either temporarily or for a considerable time.
- In Mutant UA, this exists as a psionic power known as "Parasit" (would be "Parasite" in English). The character increases one of his own attributes by stealing it from someone else, and Intelligence can be the chosen attribute.
- Warhammer Fantasy Roleplay 1st edition had the 1st level Battle Magic spell Steal Mind, which temporarily reduced its victims to a drooling vegetable capable of doing little more than gibbering and eating grass.
- Warhammer has a special rule called "Stupidity" which causes you to have to take an LD test or just wander forward, usually seen on big ugly monsters used as mounts.
- The Chaos special character Sigvald the Magnificent has this rule as well. Not because he's an idiot, but because sometimes he'll waste a turn having his bodyguards make a circle around him so he can admire himself in their mirror-polished shields.
- Several armies have magic weapons (such as the Wood Elf "Dragontooth Arrows") or abilities that cause a wounded model to be subject to the special rule, playing this trope literally. On the other hand, since it's on a model-by-model basis, and most models only have 1 wound, it's usually a wasted effort, but hey. Also, a high-level "metal" spell turns an enemy into gold statues, inducing Stupidity on nearby units through Gold Fever.
- A Harlequin weapon in Warhammer 40,000 is called the Neuro-disruptor, which "uses intricate psycho-crystalline circuitry to emit a wave of particles that disrupt the brain's neural pathways, turning the target into a drooling imbecile or killing them outright".
- In Black Crusade, this trope is one of the possible effects for a Daemon Weapon. The weapon is described as having some incorporeal parts, and the attacks go right through a target. Then they become too stupid to breathe.
- A Dragon article about Weird Gadgets for Over the Edge included the Reptilizer, which didn't just make the victim stupid, but also aggressive. You know how Mooks keep charging at the hero who's taken down their compatriots without ever wondering if maybe it's a good idea? That's why.
- The Elder Scrolls:
- Throughout the series, there are spells for reducing the skills and attributes of the target; one such spell affects Intelligence. Such spells can either be cast or used to enchant items. Thus, a weapon could be designed to make the enemy more stupid each time it hits. (Useful for taking down enemy mages, for instance.)
- In Skyrim, there are two diseases that affect Magicka: Witbane and Brain Rot. The former slows down Magicka regeneration, the latter reduces your maximum Magicka. They are contracted from being attacked by Sabre Cats and Hagravens respectively.
- NetHack's Mind Flayers have an attack that eats your brain through your nostrils, permanently reducing intelligence. It also erases knowledge of items you identified, deletes memorised spells and blanks chunks of the automap. Dropping below 3 Int is fatal, even to a character equipped with resurrection magic.
Your last thought fades away. But wait... Your medallion begins to glow! You feel much better! The medallion crumbles to dust! Unfortunately your brain is still gone.
- In Shin Megami Tensei: Strange Journey, Zelenin's Song is supposed to be so angelic, so beautiful, that anyone who hears it cannot help but lose all their will to fight and submit immediately to her. Which is rather creepy in and of itself, but then the angels get the idea of weaponizing it to subdue corrupt mercenaries, brainwash demons, and eventually assimilate all of humanity.
- 4X game Ascendancy includes the Intellect Scrambler, which temporarily erases the memories of the crew of the affected ship. The in-game description claims that it can "turn an experienced crew into a bunch of bumbling rookies".
- In Portal 2, Wheatley is an Intelligence Dampening Sphere who was created as part of GLaDOS's AI, to prevent her from killing everyone in the facility by giving her a constant stream of terrible ideas. (It doesn't work.)
- In Zak McKracken and the Alien Mindbenders by LucasArts, the villainous Caponians are using a stupidity-inducing signal over the phone networks to slowly reduce the humans' intelligence, until we're stupider than them and they can finally invade. At the end of the game, mankind reclaims its brainpower and usher in a new age of enlightenment, with telepathy and dream-sharing replacing telephones and two-headed-squirrel burgers becoming a new fad.
- Pokémon has the Simple Beam attack, a psychic laser that changes the target's Ability to Simple until it gets switched out; of course, it doesn't work if the Pokémon's Ability was already Simple to begin with. However, this can easily backfire — Simple's chief effect is doubling the results of stat changes, meaning that a Simple Pokémon can quickly become a Lethal Joke Character.
- Fallout: New Vegas DLC Old World Blues features this as a central part of its plot. The Thinks Tanks, essentially a cyborg Brain in a Jar, are a group of moral-less scientist who threatened to destroy the already post-apocalyptic world with their experiments. One of the Think Tanks, Dr. Mobius, realizes this but fails to reform his colleges, so makes them into idiots by reprogramming their robotic parts. Their stupidity serves the dual purpose of preventing them from creating more scientific hazards and preventing them from figuring out how to disable the radar fence, a feature that prevents disembodied brains (or de-brained bodies) from leaving (the think tanks think its protects the facility). Mobius then starts to play the role of an Evil Mad Scientist just to distract them so that they don't figure out that they have been made idiots, he even convinces them (without directly messing with their minds) that his robo-scorpion army is equipped with a stupidity inducing attack.
- A weapon in the DLC, the Glove of Mobius, actually makes your NPC opponents stupid by reducing their intelligence stat.
- Deus Ex: Human Revolution: The CASIE Aug works like this as it uses pheromones to reduce the target's logical thinking ability and directs them towards actions that will benefit you if you convince them with the right words as well.
- The Mind Flayers in Baldur's Gate has normal attacks that reduces your Int stats and they stack. And when your Int stat reaches 0... you die. Oh, and did I mention that they can stun your party and come in packs?
- In Dishonored 2 this can be a result of non-lethally defeating Kirin Jindosh.
- In Evil Genius some of your traps, interrogation devices, and trained social minions can do it to agents of justice. It's a highly useful technique, as not only stupefied targets become docile enough to be simply escorted away from your Elaborate Underground Base, they will also forget any incriminating activity they've seen.
- Arcanum: Of Steamworks & Magick Obscura has a unique monster called the Lethe Wyvern, named so because its poison destroys a part of its prey's memory. After several bites, the victim forgets how to run or fight and becomes an easy meal. In gameplay, critical hits from the wyvern permanently reduce the victim's Intelligence stat. Additionally, there's a bottle of wyvern's poison in a zoological museum in Tarant; drinking it also will reduce Intelligence, though anyone who does so probably didn't have much of it to begin with.
- In the backstory of the Star Control series, the Ur-Quan genetically engineered an entire species, the Dnyarri, into sub-sentience. Now just called "Talking Pets", they're used as translators since the Ur-Quan find interacting with other intelligent species to be demeaning. This was done for the heinous crime of enslaving every sentient species in that part of the galaxy with their telepathic powers, experimenting on their slaves, and committing multiple acts of genocide.
- Arle and a few other characters in Puyo Puyo have an attack called "Brain Dumbed", which is an artifact from Madou Monogatari where it was a power debuff that would temporarily decrease the intelligence of the target.
- Kevin & Kell: In one major story-arc, the Bird Conspiracy turns out to have an 'Intelligence Beam' with a... reverse setting. This results in one of the cast being threatened with the loss of a few dozen IQ points and allows another (one of the denser members) to experience a bout of "Flowers for Algernon" Syndrome.
- Girl Genius:
- During her Villainous Breakdown, Zola announces her intent to make Tarvek her loving slave... by coring out his brain with a sword.
- Dr. Vapnoople was a dangerously sociopathic spark before Baron Wulfenbach captured him. One lobotomy later, and he's barely smart enough to work as a janitor on the Baron's castle/ship.
- Eerie Cuties had an epidemic of bimbofication thanks to a powerful artefact falling into the hands of a very perverted possessed doll.
- Likewise, a poorly timed "wish" in The Wotch made all non-blonde girl bimbos.
- 8-Bit Theater:
- In a non-canon Sunday strip (actually a dream of one of the readers, that the author decided to illustrate) an enemy hits Dave with an Intelligence Extractor Ray to incapacitate him. Instead, dumb Dave reveals "a Forrest Gump-like ability to observe things and turn up at the right place at the right time" and saves the day.
- Near the end of the series Helen invents a serum that shuts down the parts of the brain that make someone a mad scientist, permanently turning them into a normal person. She briefly considers weaponizing it but decides to destroy it instead.
- In Dubious Company, one of Marty Stu's nebulously defined superpowers is being so handsome that nearly all women completely lose common sense in his presence.
- The Dumb Spring in Farce of the Three Kingdoms. In the original, it makes you dumb as in mute.
- The first protagonist of Epithet Erased, Molly, can do this to people with a touch thanks to her Epithet "Dumb". Since she has no interest in fighting and mainly uses Dumb for defense or stealth, this actually seems to be her only form of attack.
- The Adventures of Jimmy Neutron, Boy Genius uses this on himself as the entire basis of one episode when he decides to be less of a genius.
- Adventures of Sonic the Hedgehog:
- In "Grounder the Genius", Hacker creates a "Stupid Chip" as a decoy for the one with the Super Genius Program he stole from Robotnik. When Robotnik thinks he's recovered the Genius Chip, he ends up using the Stupid Chip on himself, with predictable results.
- "Attack on Pinball Fortress" had Robotnik inventing a Stupid Ray, which became the episode's MacGuffin: a crazed general thinks he can use it to make an army of brainwashed soldiers, and sleazy salesman Wes Weasley figures it will make it easier to sell people his worthless junk.
- In an episode of ChalkZone a Craniac robot hits Rudy with a "dumb dart", which is basically a toilet plunger he sticks on Rudy's head.
- One episode of Dilbert has the company initiating a merger (simply to get rid of a $20 million surplus in the budget) with "Brainsuck Industries", a bunch of poorly disguised aliens with suckers in their bellies. Dilbert derails their plans by taking the Brainsuck CEO to their marketing department — the marketing guys are so dumb that the Brainsuck chief starves to death on a full stomach, causing the aliens to flee.
- In Doug, Dr. Klotzenstien drains the brains of his fellow classmates to get the answers of a pop quiz correct. He tries to drain Quailman's, but ends up with a frog's.
- DuckTales (2017): In "Double-O-Duck in You Only Crash Twice!", Black Heron creates a ray that can make creatures more intelligent. Her initial plan is to reverse it and use it on Scrooge McDuck, making him "dumber than the dummies"; however, Steelbeak later uses it on her and plots to use it to make the entirety of Duckburg Too Dumb to Live.
- In Futurama, an invading alien race of brains can sap intelligence away by their presence, which makes it easier to assimilate knowledge and destroy planets. It doesn't work on Fry, however, because he has an unusual brain quirk (which, implicitly, explains his general lack of intelligence).
Nibblonian 1: It's a genetic abnormality which resulted when you went back in time and performed certain actions which made you your own grandfather.
Fry: I did do the nasty in the pasty.
- Invader Zim:
- In "Nanozim", Zim attempts to use this on Dib by shrinking to microscopic size and destroying his intellect from within. "I'll just go to your brain and delete the knowledge of where you hid the master disk! And, as an added bonus, I might as well make your entire brain... nn-not smart... no more."
- In "Plague of Babies", Zim does this successfully — he fends off a horde of aliens who are fully sentient but visually similar to human infants by combining GIR with a power amplifier to create a lobotomizing wave that destroys their minds. He then returns them to their covers as real babies to random parents (where they had already been hiding as oddly unaging babies for 8-years). Yeah Invader Zim is kind of disturbing that way.
- In the third special of The Jimmy Timmy Power Hour, the enemy gets the edge by robbing Jimmy of his genius intelligence (and Timmy of his fairies). He isn't as stupid as in the other example, but aside from his lack of scientific know-how he also acts much ditzier than usual, forgetting common words and such.
- In one Kim Possible episode, Drakken uses "Silly Hats" to avenge himself on the members of the Cerebellum Ultra-Smart Super Genius Thinking Society for not letting him join.
- In the Lilo & Stitch: The Series episode "Spike", Jumba reveals that one of his earlier experiments had quills that contained a venom which reduces anybody's intelligence to 1% of its original functionality. Strangely, it doesn't seem to affect him, but he later clarifies that it does, it's just that he's so smart that even 1% of his usual intelligence seems normal.
- Miraculous Ladybug
- In "Simpleman", the titular akuma's main power (making things "simpler") also has this application, "simplifying" the minds of whoever it hits. As a result, motorists just drive in straight lines because it's simpler than turning, the local pizza place and ice cream stand only have one kind of pizza/ice cream on the menu because it's simpler than having a variety to choose from, the pizza delivery guy rides around tossing out pizzas to everyone he sees because it's simpler than trying to figure out who did or didn't order one, and Ladybug and Cat Noir nearly trade away their Miraculous to Simpleman for candy.
- In "Risk", the aptly-named titular akuma sings a song that makes those who hear it less cautious and more susceptible to taking chances. Some of the resulting risks work out well, but others not so much — in the second half of the episode, Ladybug takes a chance and uses a plan that involves recruiting Adrien to use the Dog Miraculous when she could've used it herself. As a result, she inadvertently recruits Félix (who had pulled a Twin Switch with Adrien), and he betrays her, using the Dog Miraculous to steal her yoyo and hand it over to Gabriel so he can steal every Miraculous in the Miracle Box.
- In Pinky and the Brain, the newest dance craze (a parody of the Macarena) is actually engineered to make those who perform it gradually more and more stupid, as Brain is stunned to learn. (Only the first verse, however. The second verse, which Brain prevents people from learning, makes people act like cats.) It's unclear whether the dance affects Pinky, though.
- In the Rick and Morty episode "Something Ricked This Way Comes", Mr. Needful gives Rick a microscope that lets him "see things beyond comprehension". Upon having it analyzed, he learns that its actual purpose is to make him mentally retarded and thus too stupid to understand anything.
- Rocky and Bullwinkle has Goof Gas in one arc. "One poof, you're a goof!", as Boris puts it. It doesn't work on Bullwinkle, though.
Boris: No brain, no effect!
- SpongeBob SquarePants: Mermaid Man and Barnacle Boy have the "Orb of Confusion", a literal Idiot Ball which turns anyone in its range into a drooling idiot. Unfortunately, the range of the Orb is only a few feet, so it only affects the holders.
- In the Superfriends episode "Around the World In 80 Riddles", the Riddler sprays Batman, Robin, Wonder Woman, and Superman with his "Stupid Spray", which slowly saps its victims of their intelligence. He then leads the heroes on a riddle and booby-trap filled chase around the world, stalling for time until the spray completely takes hold. At the end, the heroes become reduced to toddler-like intelligence but manage to grab the antidote and defeat Riddler.
- The Transformers: According to the production material, at least, Wreck-Gar packs a ranged weapon that temporarily does this.