A device or effect that makes people less intelligent. (Usually temporarily.)
Generally played for comedy, with the afflicted people talking in exaggerated "stupid" dialect and making decisions that are a Take That! against whatever the writers oppose. In almost all cases, the effect hits both "book smarts" and "common sense", even though they're different kinds of intelligence. For extra fun, one character will be functionally immune to the effect due to already being stupid.
When someone's using this as a weapon, it's a type of Stupidity-Inducing Attack.
Contrast Genius Serum.
- The Judge Dredd comic had an experimental weapon named "the Stupid Gun." It fell into the wrong hands—Hilarity Ensues.
- In Super Mario Bros. #5 (from Valiant Comics), King Koopa's (full name "Bowser Koopa") science team comes up with "the Stoopid Bomb." The King of the Mushroom Kingdom, being an idiot, is unaffected, but everyone else becomes foolish, including King Koopa's own troops, as the bombs are on a hair trigger and keep getting dropped. There are also antidote Smart Bombs, but they are all used on one Shyguy, who becomes a genius and temporarily wrests control from Koopa. Too bad he's now the Only Sane Man.
- The end of the President Evil arc in The DCU explained Lex Luthor's blaming Superman for a kryptonite meteor heading for Earth, putting on Powered Armor, and ranting madly on national TV, by him having injected himself with a mind-altering mixture of Bane's Venom formula and liquid kryptonite. Why he decided he needed some pretty low level Super Strength despite being the President of the United States is definitely Plot-Induced Stupidity though. Damn you Loeb.
- Drinking green, radiated rocks from outer space in liquid form is even worse. And don't forget this IS the guy who had cancer because he wore a Kryptonite ring all the time.
- Geoff Johns later threw in a revelation that Lex's recent bouts of stupidity were caused by the presence of his Alternate Universe 'counterpart', Alex Luthor Jr. Somehow. Even though he is actually the son of his universe's Lex.
- The above gets some possibly unintentional Fridge Brilliance from the fact that before Luthor's total breakdown, in Adventures of Superman #600, he had a brief period of amnesia during which he became a radical anti-corporate villain, in essence, the opposite of regular-Luthor. During this story, he called himself ... Alex.
- In the utterly depressing alternate Marvel Universe that serves as the setting for Mutant X, there is a Dumb Muscle character called The Brute. He used to be brilliant scientist Hank McCoy before his notorious Professor Guinea Pig tendencies took a tragic turn, leaving him too stupid to figure out how to reverse what he'd done to himself.
- Maul of the comic book Wild CA Ts has size-changing powers that makes his intelligence inversely proportional. Not only does growing make him dumber, he later discovers he can shrink to get smarter, although this proves exhausting.
- Mentioned offhand in Megamind when the main character says that one of his planned inventions was an illiteracy beam.
- The Cabin in the Woods: The Organization put a chemical in Jules's blonde hair dye that makes her behave more stupid and slutty than she really is, as they force the various occupants of the cabin to fill their typical Slasher Movie roles. Jules is actually pretty intelligent, being pre-med.
- In Monster!, the curse on the town of New Purgatory means that every three years when the title Monster resurrects and goes on its rampage, the town is forced to abide by horror movie rules, which includes making people act in line with those rules. As a result, everyone but the 'movie's' designated protagonist will be Genre Blind and Police Are Useless is Enforced.
- There was at least one Airport Fantasy-style disaster novel which had this effect as the result of a communicable disease. Toward the end, a newscaster (who is having trouble reading the TelePrompTer) notes that sales of all literature except pornography have fallen drastically. The heroes finally found a cure, but were uncertain if anyone would want it anymore.
- This sounds like IQ 83 by Arthur Herzog.
- "Bimbo Rays" are popular in certain kinds of fetish fiction.
- "AUM" in the Illuminatus! trilogy is a hallucinogenic drug cocktail that renders users highly creative and supremely gullible at once. When one character tests it by spiking the punch at a meeting of a Fictional Counterpart to the Knights of Columbus, the group ends up renouncing Christ and adopting geocentrism.
- Unlike most examples, this stuff tends to make people more intelligent, not less. Initially they believe almost everything that follows some kind of logic, but since it stimulates inquisitivness and curiosity, it tends to produce more knowledgeable and open-minded people, on average. It's implied that sometimes the opposite can happen as well, but those examples are never seen in the book.
- In the short, short story I Wish I May, I Wish I Might by Bill Pronzini, a retarded boy finds a genie in a bottle which offers to grant him three wishes. One of them? "I'm going to wish for all the little boys and girls in the world to be just like me so I'll never-ever be without somebody to play with."
- An example where the change is permanent, the Stephen King short story The End of the Whole Mess, is about two brothers who release Phlebotinum into the world's water supply in order to make everyone less aggressive. At first, the plan appears to work, as war and violence become a thing of the past. Unfortunately, after going back to the town where they got the substance, the brothers learn that another, less pleasant effect is the onset of dementia. The story ends with the implication that humanity will go extinct as everyone on Earth forgets basic living skills.
- The novel Bimbos of the Death Sun is centered around the author of a novel within a novel with the same name, whose basic premise involves solar radiation messing up computers; as a side effect, it also make women world-wide lose intelligence. Despite what it sounds like, he wasn't doing it to make any kind of social point or be chauvinistic — the idea was simply based off of the fact that some diseases are linked to sex.
- In Robert L. Forward's Rocheworld, the ship's crew are given a drug (NoDie) that greatly extends their lifespans at the expense of making them stupid. The ship's AI stops administering the drug when they get to their destination, and their intelligence comes back.
- In Stargate Atlantis the Wraith serum raises physical abilities but seriously dampens intelligence.
- Buffy the Vampire Slayer:
Xander: And was there a lesson in all this? huh? What did we learn about beer?Cave Buffy: Foamy.Xander: Good, just as long as that's clear.
- "Beer Bad". Buffy drinks cursed beer which turns her into a cavewoman. (Although she still looks the same, the guys who drink the beer literally look like cavemen. Granted, Xander expressly cut her off before the rest) Ends with a Spoof Aesop:
Giles: I can't believe you served Buffy that beer.Xander: I didn't know it was evil.Giles: You knew it was beer!
- Of course, the beer itself wasn't a good idea for someone who can literally punch through car doors.
- "Band Candy" had Ethan Rayne selling chocolate that made people act like particularly irresponsible teenagers. This is notable because "book smarts" weren't affected so much as common sense was. Buffy wound up having to be the responsible, mature one.
- It seemed to depend on what sort of person the reverted individual was as a teen. The principal was, and became again, a dweeb and mindless hanger-on to whoever seemed coolest (in this case, Buffy.) Giles was, and became again, a danger to everyone around him.
- In the Eureka episode "E=MC...?", eating cloned chicken meat causes most of the town to lose their knowledge, common sense, attention span, emotional maturity, etc.
- Monty Python's Flying Circus - In the "Gumby Surgery" sketch, the head surgeon (Graham Chapman) is perfectly intelligent and lucid while asking the nurse for glasses, mustache, and handkerchief. As soon as the latter is put on, he turns into the usual Gumby idiot/madman: "I'm going to operate!"
- Star Trek: The Original Series: In "The Cloud Minders", the mineral zenite emits a colorless, odorless gas that decreases intelligence and increases aggression. Fortunately, removing the subject from exposure makes the effects gradually wear off, and a simple filter mask can protect one from exposure.
- In Tom the Dancing Bug, "Flowers for Trinitron" uses this trope to create "Flowers for Algernon" Syndrome. A television causes stupidity. A man is watching NYPD Blue when the cable goes out. The man, cut from TV, becomes gradually smarter over the next six days. He reads East of Eden, volunteers at a homeless shelter, and shifts his handwriting from print to cursive. He is about to destroy his TV, when the cable comes back and Wheel of Fortune comes on. The man soon reverts to stupidity.
- Calvin and Hobbes:
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.
- In the Dungeons & Dragons campaign setting Ravenloft, the mysterious Dark Powers that control the Demiplane of Dread maintain this as a general effect on the inhabitants so that they do not question the bizarre nature of the world they live in or the way its individual domains cross different Technology Levels and genres. For example, the inhabitants of the domain of Lamordia (based on Frankenstein), are not great believers in magic despite the neighboring domain of Darkon being a Standard Fantasy Setting.
- One of the Vahki models in BIONICLE had the ability to temporarily overwrite a Matoran's consciousness and turn them into a mindless "shambler" incapable of rational thought.
- It also occurred to Vezok when he got a Literal Split Personality - the original Vezok lost a few IQ points because the part split off got his ability to think tactically.
- In Psychonauts, using super-powerful sneezing powder to make people literally sneeze their brains out results in the person turning into a listless zombie obsessed with television (and hacky-sack, for some reason).
- The trope is also inverted in the case of Ford Cruller, who (due to a crippling psychic battle) is schizophrenic and amnesic when he's not near the Psitanium deposit.
- The Confusion power is a psychic ability that induces confusion on others. This manifests in the form of a question mark, the dot used like a grenade, creating a temporary cloud of green smoke. Enemies hit with it attack other enemies, NPCs give disoriented dialogue, and if Raz is affected by an enemy's Confusion gas, the screen becomes blurry and the controls are reversed.
- The plot of the point-and-click adventure game Zak McKracken and the Alien Mindbenders revolves around aliens who took over the phone company and are sending out a signal that makes people stupid.
- In Soul Nomad & the World Eaters, Danette appears to be The Ditz for much of the game, but it turns out that the block on her memories is to blame. When it's finally removed, she's only a little bit ditzy.
- In the first Djinn arc of The Wotch, a wish turns all girls except blondes into stupid bimbos.
- SCP Foundation: SCP-714 is a ring that, among other symptoms, reduces the wearer's mental capacity, but also makes them resistant to other forms of mental manipulation.
- In the Futurama episode "The Day the Earth Stood Stupid", Fry is the only one immune to the giant brains' stupefying effect due to a deformity in his brainwaves caused by his... unique ancestry. In practice, this basically means he's already so stupid that the brains can't make him any stupider.
- In an episode of ChalkZone, Craniac 3 tries to get Rudy with a smart bomb. It is sentient, though, and does not want to blow itself up. He instead opts for the Dumb Dart, which lowers intelligence.
- An episode of Kim Possible had Dr. Drakken using "silly hats" to reduce the world's leading scientists to blithering idiots.
- Adventures of Sonic the Hedgehog:
- In "Grounder the Genius", Dr. Robotnik invents a helmet that uses a microchip to increase his already high intelligence. Near the end of the episode, the chip is swapped out with one that makes him stupid instead.
- In "Attack on Pinball Fortress", Robotnik builds a ray that he plans to use to make the population of Mobius stupid so they can be easily ruled. While Sonic wants to destroy it, Sergeant Doberman wants it because stupid soldiers are easier to train, while Wes Weasley wants it because stupid customers are easier to sell to.
- In an early episode of The Adventures of Jimmy Neutron: Boy Genius Jimmy has a brief bout of "Flowers for Algernon" Syndrome and builds a "brain drain" helmet to lower his intelligence to that of an average person, but it accidentally gets cranked up to maximum stupidity without him noticing, and turns him into a total idiot.
- SpongeBob SquarePants:
- "You won't get away Man-Ray; not while we have the Orb of Confusion!" Which, by the way, causes a wave of confusion that starts with the person who turned it on, making it a very literal Idiot Ball.
- The episode "Salsa Imbecilicus" has Plankton making salsa with Patrick's DNA that makes almost everyone in Bikini Bottom as dumb as Patrick, himself included.
- An episode of Rocky and Bullwinkle featured "goof gas". Bullwinkle was too stupid to be affected by it. Boris remarked something like, "Goof gas affects the brain. No brain, no effect." Pretty much the exact same thing, with different phlebotinum, happened in The Movie.
- An episode of Invader Zim had a power amplifier that "radiated pure stupid" when GIR hooked himself up to it.
- In the ReBoot episode "Enzo the Smart", Enzo messes with the clock speed of Mainframe in an attempt to make himself smarter. He asks it to make him twice as smart as everyone. Instead of making him smarter, it just makes everyone twice as stupid as him.
- The Simpsons: Homer Simpson's stupidity isn't natural: a crayon lodged in his brain takes 50 points away from his previously average IQ. This is worsened by the fact that the nuclear power plant where he works doesn't use proper shielding. All the slapstick violence in the form of blows to the head certainly can't help, either. Word of God is that he loses 5 IQ points a season from brain damage, and at this point he's basically "a dog that can talk."note
- Used as a brief gag at the end of one episode of Buzz Lightyear of Star Command. Robot Buddy XR has had files he's not supposed to have on his brain chip throughout the episode. At the end he deletes them. However, he also erases most of his IQ by mistake.
- Played with in an I.M Weasel short on Cow and Chicken, in which I.R. Baboon managed to publish a book that apparently turns everyone who reads it into complete and utter idiots. Lamenting on this turn of events, I.M. Weasel decides to expose himself to the "stupid powers"... but remains unaffected. He eventually realizes that everyone around him was already a stupid twit and he just didn't notice it.
- Lilo & Stitch: The Series has Experiment 319, named Spike, who can spray spikes that raises people's silliness by 99%, leaving them only 1% clever.
- The Penguins of Madagascar:
- In the episode "Sting Operation," the penguins use one of Kowalski's inventions to make themselves stupid so that they can't feel the hornets' stings.
- In another episode, Kowalski's attempt to boost his intelligence backfires and makes him stupid instead.
- Johnny Test: Susan and Mary Test built an intelligence amplification machine, and Johnny used it to give them an IQ of 22.
- Dogstar: In "Mensamania", Fenwick creates a stupidity virus which Bob Santino unleashes on Mensa, the most intelligent planet in the galaxy as a test run. If it works there, he intends to use it on Earth to make the population stupid enough to buy his latest product.
- In Teen Titans Go!, Beast Boy becomes sick of being the team's idiot, so he steals Raven's spellbook to make himself smarter with magic. When he screws that up, he realizes that to have a similar effect, he can just make everyone else on his team dumber than he is. He succeeds at that, but becomes frustrated with having to take care of four people who are bordering on Too Dumb to Live. He decides to fix the dynamic... by making himself even dumber than his brain-drained teammates.
- Xiaolin Showdown features the Woozy Shooter, whose effect consists of creating a mist that makes its targets hallucinate and act madly goofy. The Ring of Nine Dragons also has a similar effect as splitting yourself into nine duplicates of yourself only divides your brainpower instead of increasing it.
- DuckTales (2017): In "Double-O-Duck in You Only Crash Twice!", Black Heron builds an intelligence-draining ray that she plans to use on Scrooge. Steelbeak ends up using it on her after she presses his Berserk Button one too many times, then later plans to make Duckburg literally Too Dumb to Live. It also has a reverse setting.
- She-Ra and the Princesses of Power has the First One's disk, which is capable of infecting many forms of technology as shown in "System Failure" and "White Out". This includes She-Ra's sword, which causes Adora to act like she's heavily drunk.
- In the Family Guy episode "Baby Stewie", Brian convinces Stewie that he'll lose his genius intellect when he grows older, so Stewie builds a machine to rewrite his DNA and keep himself smart. It instead reduces his intelligence to that of a normal 1-year-old.
- CatDog: In "Smarter Than the Average Dog", Cat tries to make Dog smarter with educational videotapes. As a result, Dog becomes smarter to the point where his brain expands, while Cat has his intelligence drained and becomes a pinheaded dolt.
Dumb!Cat: You... You d-did this to me, bow-wow person! You made the smart go bye-bye!
- Ethyl alcohol.
- Sleep deprivation.
- Various drugs (legal and otherwise), can cause this.
- Many pharmaceutical drugs have temporary side effects that cause dizziness, lethargy, and inability to focus.
- Most recreational drugs have a much more pronounced version of this effect, especially when the intended effect is to produce some kind of euphoric state. Of course it can also be because it's causing brain damage.