My Skull Runneth Over

Talk about mind-blowing!

"The wizard who reads a thousand books is powerful. The wizard who memorizes a thousand books is insane."

— Flavor text on the Magic: The Gathering card "Battle of Wits"

So you're walking along, minding your own business, playing with your iPod in a neutron storm next to a nuclear plant during the equinox, and suddenly some Applied Phlebotinum grants you a magnificent gift: an entire library's worth of information is downloaded directly into your head, along with all the intellect, memories and wisdom needed to use it. You become an instant genius at everything from knitting to astrophysics, and you can suddenly Technobabble your way out of any problem!

Except... for this problem:

The thing about super-human knowledge and intellect, is that often you don't get a super-human brain to put it in, and there's only so much room in there. As your brainpower goes up, your survival rate goes down. Time is running out, and you either have to figure out a way to ditch your new super-smarts or die — either by hemorrhage, cranial explosion, or body strain. Maybe the knowledge contains details about things man was not meant to know, and your body will try to adapt to it involuntarily with your new knowledge.

Occasionally, dying isn't the problem: It might be non-fatal, but have some other significant drawback if you don't get rid of it soon, such as madness, head-splitting migraines, overwriting of memories or knowledge, or permanent brain damage. Perhaps you simply become unable to store new memories until you clear some space. This often leads to "Flowers for Algernon" Syndrome when the character returns to normal, warning others about the dangers of get-smart-quick schemes. Fairly common in Cosmic Horror Stories when a protagonist obtains a legible Tome of Eldritch Lore and doesn't stop reading it soon enough before they Go Mad from the Revelation.

Compare Deadly Upgrade and Too Much for Man to Handle. Also compare The Fog of Ages, where an immortal being has been collecting memories for so long that they're overwriting the oldest ones. Not to be confused with My Brain Is Big, where the skull literally runneth over and the brain shows outside it, although that trope can manifest as a consequence of this one. Nor is it to be confused with Too Much Information. See also Super-Intelligence and A Mind Is a Terrible Thing to Read.

As this is a Death Trope, unmarked spoilers abound. Beware.

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Examples:

Anime & Manga

• Played for Laughs in Chapter 7 of Asteroid in Love. After Misa hears Mira complaining her difficulties in memorizing all the formulae used in physics, Misa suggested Mira just derive those herself. Mira immediately gets Blank White Eyes with steam coming out from her skull...
  Suzu: Misa-nee! Mira's gonna explode!
• Ryo in Bocchi the Rock! has a similar situation as K-On!'s Yui — she's usually Book Dumb due to being a Ridiculous Procrastinator, though she is able to get great results if she puts in effort... which usually means she will forget how to do things like playing the bass.
• Cosmo from Chainsaw Man can overload people's minds to the point that they are unable to think of or say anything other than "Halloween" ad infinitum until they die. "Santa Claus" is sure her Hive Mind is too massive to be hurt by her, so Cosmo (a.k.a. the Cosmos Fiend) specifies she inflicts total understanding of the universe on a person. Santa Claus' knowledge not taking up one page in Cosmo's mental Great Big Library of Everything, her mind is destroyed just like any other's. Appropriately, Cosmo can be identified as a Fiend by her brain spilling out of her head. However, this seems to require some start-up time, as Makima decapitates and kills her nigh instantly with no difficulty and no chance to retaliate.
• In Death Note, this happens to Light Yagami when he regains memories of the Death Note. However, he regains his composure within a few seconds because this was part of his plan.
• At the end of Divergence Eve, LeBlanc gets all of the information about the entire universe (and the alternative one) downloaded to his brain in a bid to learn how to become immortal. The information overload is too much for his brain to handle, and his head explodes.
• In Fullmetal Alchemist, this is how Ed describes the feeling of going past the Gate of Truth that connects humans with the ability to use alchemy. It doesn't stop him from wanting to repeat the experience, since he did gain an immense amount of knowledge from it.
• In Ghost Sweeper Mikami, Dr. Chaos' brain really is completely full of information (due to him living for several hundred years). So what happens when he learns something new? Rather than expand and strain itself, his brain simply overwrites the earliest thing it can, so while he is an occult genius who can readily comprehend many mystic things, he can easily forget such basic things as what 2+2 results in (hint: not 5).
• In Gundam 00: A Wakening of the Trailblazer, this happens to any developing Innovator who tries to psychically connect with the ELS. One describes what he hears from them as "nothing but an endless cry". It later turns out that the ELS didn't realize the incredible volume of information they were broadcasting was harmful to human minds, which were too small to contain it all. Once they figure that out, it's implied that they learn to communicate with Innovators without overloading them.
• Played for Laughs in K-On! when Cloudcuckoolander Yui completely forgets how to play the guitar after cramming for an exam. It later becomes a recurring issue for Yui through both seasons of the anime adaptation.
  Yui: [after being greeted by the others the morning before a final exam] Don't talk to me. Everything I memorized will fall out. [trips]
• The titular character of Naruto faces this downside to his Shadow Clone training strategy. With hundreds of clones, he can experience years of training in one day, but the backlash when the clones disperse is enough to render him unconscious while his brain tries to process the information.
• In Omamori Himari, back when Kuesu Jinguuji was a student mage, her only friend in the school got her to read a forbidden tome of knowledge. Then it turned out that the only reason that Vilma befriended Kuesu in the first place was because she thought that reading the book through a second person would allow her to acquire the tome's infinite knowledge without going mad like every other person who'd tried to read the book. Unfortunately for her, Kuesu was so suited for use as a medium that she absorbed knowledge faster than Vilma's mind could process it, resulting in her brain exploding.
• In the Phoenix story "Civil War", the historical figure Taira no Kiyomori desires the blood of the titular bird so he can become immortal and continue to lead the Taira Clan, instead of letting it get run into the ground by his incompetent sons. He starts having second thoughts, however when he has a vision of himself in the 21st century, where he's become an invalid due to his brain having run out of space for new memories and has to be periodically hooked up to an "Amnesia Machine" or he'll go crazy. Other characters who do gain immortality, or at least very long lifespans don't seem to have this problem, but that might just be because they usually end up becoming hermits whose lives are largely monotonous.
• In Silent Möbius, Holonic, a computer virus that consumed almost all of Tokyo's data, was going to attempt to enter a visionary's brain and escape physically, and this trope is what Lebia Maverick described as what would happen if it did.
• In Stardust Telepath, when Yuu finds herself dumbfounded by Raimon's explanation about how model rockets work, she tries to take a shortcut and use forehead telepathy to download the knowledge directly. However, it immediately backfires when the dense technical knowledge blows her off her feet.

Comic Books

• The Adventures of Barry Ween, Boy Genius: The titular character is a Child Prodigy with an Impossibly High IQ of 350. As a result, his brain is constantly firing on all cylinders, leaving him physically unable to relax or even sleep. He predicts that he'll be driven mad by the time he turns 21 and only attends school in the hopes that regular human interaction will prevent it.
• Captain Atom: In Captain Atom: Armageddon, Captain Atom does this to Voodoo when she tries to invade his mind. He uses his neural uplink to the Pentagon's computer net to basically KO her with the Internet.
• Dylan Dog: In one issue, a scientist is looking for a way to unlock the full potential of the human intellect, but all of his test subjects die in predictably gruesome ways. It turns out that an adult's intellect is "atrophied" after a life of underuse, and only babies are flexible enough to survive the process. When the scientist, mentally unbalanced after years of frustrations, experiments on his newborn daughter, it finally works but it works too well.
• The Incredible Hulk: In his first appearance, the Leader is after an Ultimate Machine containing all the knowledge in the Universe. When he obtains it and downloads the information into his mind, this proves too much even for his super-brain and seemingly kills him.
  • Later on in Thunderbolts (2012), having long since reached the physical limit on his constantly growing intellect, the Leader parceled it out in uploads to servers accessible over the internet with the correct code. When he gives his brother access to one the influx of information drastically inflates his head before it bursts.
• PS238:
  • A scientist managed to both figure out time travel and learn all of the world's knowledge up to the late 90s by uploading an encyclopedia into his brain. It combined with continual unshielded exposure to the 4th Dimension made him so crazy that he used his time travel abilities to be both a superhero and his own nemesis.
  • Somewhat similarly, Lyle is a kid who has the ability to see patterns to the point where he can pretty much instantly know everything that has and will happened to the people and things around him. It's so overwhelming that he spends most of his time "in a white room listening to music" until he uses his power to get someone with Power Nullifier abilities a job at the school.
• Ruins: Mystique dies due to her brain being unable to cope with the various personalities and identities she'd accumulated thanks to her Voluntary Shapeshifting powers.
• The Sandman (1989): In "Calliope", Dream punishes an author by giving him an overload of ideas, so much so that he starts writing them on the walls with his bloody fingers.
• Spider-Man: In The Gathering of Five, Norman Osborn and a few others engage in a magical ritual that will grant them each individually, amongst other boons, either madness or knowledge. When the ritual is completed, one of the participants suddenly starts babbling nonsense, leading Osborn to believe he had been struck with madness. It eventually turns out that it was Osborn that had been struck with madness, the man who started babbling was granted knowledge, all knowledge, of everything. Eventually he manages to assume normal behavior, and he can freely access this knowledge, but doing so essentially puts him through a seizure every time.
• The Transformers: Lost Light: A glimpse of the future in the final issue shows that Rewind eventually uploads so much information into his mental database that he corrupts his brain and forgets how to transform out of his memory stick mode.
• The Mighty Thor: Odin briefly does this to Iron Man at one point, when the latter questions the wisdom of his decisions. He doesn't give Tony enough knowledge to drive him insane or kill him, but just enough of a glimpse of the cosmos to humble him and paralyze him for a while.
• X-Men: In The Dark Phoenix Saga, after Mastermind's manipulations cause Phoenix to give free rein to her dark side, she psychically feeds him enough cosmic power and knowledge to overload his brain, and then almost immediately takes it away. The fleeting taste of cosmic awareness leaves him catatonic.

Comic Strips

• The Far Side spoofs this in one comic. A student with a comically tiny head raises his hand in a classroom and asks the teacher, "May I be excused? My brain is full."

Fan Works

• In Ashes of the Past, the first time Ash's Absol Mega-Evolves, her Danger Sense is overclocked to the point that all the information about disasters surging into her head at once drives her berserk.
• In Boldores and Boomsticks, a temporary version occurs whenever a human with an unlocked Aura uses a TM to learn a move. They have a seizure while the device is running, and afterwards have a migraine from the overload of information being forced into their mind at once.
• Dungeon Keeper Ami: From "Trapped (second half)," Ami passses out from her Dungeon Heart's information when she reconnects with it, and so ends the chapter:
  Far away, her dungeon heart sluggishly awakened from slumber. Her awareness was limited to its immediate surroundings, as everything further than a few metres away remained hidden behind a curtain of darkness. Tile by tile, this darkness receded, as if she was rapidly claiming the territory.
  The wave of expanding awareness reached the first intersection and rushed down each of the three outgoing tunnels simultaneously. Everything it passed provided information. The state of the walls, the clicking of traps rearming themselves, the amount of water within the pipes within the wall.
  Another intersection, and yet another. The rush of knowledge sped up exponentially. The amount of gold and gems in her treasury. The number of withered plants in one of the farms. An imp, rubbing her eyes in confusion. More intersections.
  Ami grabbed her head in discomfort as the flashes of knowledge came faster and faster, too quickly for her to process them. They produced a sensation like pins and needles, multiplied by the size of her dungeon.
  Running goblins. Armoury. Swords, daggers, clubs. Half-finished reaperbot. Frost patterns. Wandering civilian. Right angles. Aquamarine tiles. Dripping water. Trolls. Beakers. Cables. Mixed patrol. Intruders. Gems. Dragon. Tall ceilings, right angles. Pools and water. Warlocks. Slender pillars. Chatting dark elves. Intersectio-
  The flood of information became too great for her tired mind to handle. Already weakened from draining her own life energy, she slowly toppled forward from her seated position, unconscious.​
• Hybrid Hive: Eat Shard?: Since Taylor's Unison Device consumed her shard connection, Taylor can still use her canonical bug control when she chooses to. However, without a corona pollentia and gemma in her brain, the multitasking systems aren't on the same level as the shard would have provided, leaving her thoroughly overwhelmed whenever she switches the ability on. She decides to bite the bullet and keep it on for several hours, in order to adapt, but after an hour the Device automatically switches it off again to avoid permanent brain damage.
  Hive: The sheer number of inputs from the insect control systems far exceeded your brain's ability to process, even with the multitasking systems providing outside assistance. ... For your own safety the insect control system is currently locked until you have recovered from this attempt, I estimate that will take at least four days, during which I will also refrain from utilizing the multitasking systems while you’re sleeping.
• In Luminosity, through a series of various events, Elspeth finds herself with the entire collected memories of nearly every vampire in the world, and the ability to blast it into others' minds. Acquiring all this information knocked her out for a good few hours, and does the same when used on vampires or half-vampires — but when used on humans, it breaks them. But it's possible to put some of the pieces back together, functionally resurrecting one of the vampires whose memories were part of the blast. This is discovered when it accidentally resurrects one random vampire and one very plot-important one, and then used deliberately to bring back the Clearwaters.
• In On the Edge of the Devil's Backbone, Ezra's empathic abilities overload at one point and he senses every living being on Lothal at once. Kanan also gets drugged with a substance that makes him see and feel everything at all points in time, and desperately tries to claw his own brain out while begging for it to stop.
• Starting Over Again: When Starlight accidentally traps herself in a time loop that erases her memory every 18 hours, Twilight creates a crown that stores her memories and gives them to her at the beginning of each new day. Many years later, Queen Chrysalis is trying to conquer Equestria and gets into a magic showdown with Starlight. Astonished by the unicorn's power, she concludes that Starlight's crown must be the source of it, grabs it and puts it on her own head. Trying to absorb all of Starlight's memories at once destroys her brain and permanently reduces her intellect to the level of a newborn baby. Pinkie's only comment is, "I'm not babysitting."
• Princess Luna suffers this in Through the Eyes of Another Pony when she magically memorizes the entire Internet. It seemed like a good idea at the time! Side effects may include increased cynicism, horrible pop-culture jokes, temporary severe speech impediments, and severe outbreaks of emo.
• In With Strings Attached, the first time Ringo uses his mindsight, his brain is overloaded with a million brilliant details all screaming for his attention. Luckily, before he can go nuts, "A reflex he didn't know he had kicked in and narrowed his vision back down before anything permanent happened." By The Keys Stand Alone: The Soft World, though, he's able to handle all that detail — indeed, he's addicted to it, and when he can't use his mindsight, he finds the world hopelessly drab, shallow, and slow.
• With This Ring: Paul makes the mistake of giving his ring an overly open-ended instruction to find the missiles, and experiences "A brief and mindchurningly horrifying moment as the ring tries to show me every rocket based weapon in Asia."

Films — Animated

• Twice in Superman Unbound: Brainiac hooks Superman up to his archive and starts downloading, betting that Superman's brain would liquefy after only one world. Superman then beats Brainiac by taking him out of his ship, overloading him with the constant shifting data of a living world which he so desperately tries to contain in his bottled cities.

Films — Live-Action

• In Arena, the (coincidentally named) character "Skull" meets his end this way. When Steve competes in the final arena fight at the end of the film, Skull connects his brain to, and sabotages, the handicap computer controlling the skill match-up between Steve and his opponent. When Steve's co-worker, Shorty, suspects foul play, he goes to investigate. When fighting the arena manager's enforcer, Shorty gets thrown into the handicap computer, causing it to overload, and eventually, causes Skull's head to explode:
  Skull: [frantic] Full in the skull, full in the skull! [a few shots later, his head sparks and explodes]
• Batman Forever: Though a bit vague, Riddler seems to be doing this. (That, or using other people's brainpower to amp his own mental function, or both.) It makes him a megalomaniac and a malfunction of the machine physically warps him.
• The Butterfly Effect: Thanks to Mental Time Travel, the hero suffers mental instability, migraines, and institutionalization when the doctors find out "he has four lifetimes' worth of memories in his head!" And this isn't taking into account his nosebleeds, results of said memories overloading his brain.
• In Charly, an adaptation of the classic Flowers for Algernon, an intellectually handicapped man undergoes a treatment that boosts his intellect up to normal and then far beyond. Unfortunately, as he discovers from checking out the test rodent Algernon, it'll cause him to burn out and wind up even stupider than before, possibly brain-dead.
• In the 1995 version of The Computer Wore Tennis Shoes, the implanted knowledge was not going to destroy the recipient in this case, but it's erased with a magical noise virus over the phone.
• Eternals: Thena is going insane because she has too many memories, in part because of her mindwipe after their last mission not being entirely successful.
• Subverted in Flash Gordon (1980), in that Zarkov's brain is to be erased and reprogrammed, but Klytus orders it to be done "only to Level 3", as he doubts that Zarkov's Earth brain can take any higher level. After he leaves, his assistant orders him to be programmed to Level 6. Further subverted in that Zarkov manages to also keep his original memory.
• In Flight of the Navigator, an alien research computer travelling near Earth, hearing that humans "only use 10% of our brains", wants to find out if it could use the other 90% to back up its data. When the abducted experimental subject asks it what happened after it fills his brain to the max, the computer replies "You leak." Fortunately, there are no dangerous side-effects.
• Doctor Ostrow suffers this fate near the end of Forbidden Planet after intentionally overusing a Krell learning machine to try to figure out what's killing them.
• At the end of Indiana Jones and the Kingdom of the Crystal Skull, Irina Spalko gets all the knowledge the aliens possess downloaded into her mind, but it's so much that her head (and then the rest of her) explodes.
• Johnny Mnemonic has the additional kick that the protagonist doesn't actually have access to the downloaded knowledge that's killing him — he's a Courier hired to carry data securely in his own "wetware".
• Downplayed in The Man Who Knew Infinity, in which the titular character, Srinivasa Ramanujan, suffers anxiety from the seemingly divinely revealed mathematical discoveries he constantly experiences and a strong sense of urgency to have them known to the world.
• In Phenomenon, George Malley has a UFO encounter that gives him advanced brain processing power and telekinesis. However, it also gives him a brain tumor. Also, there was no UFO — that was a hallucination caused by a seizure triggered by the brain tumor.
• Spock almost does this to himself when attempting a mind-meld with V'Ger in Star Trek: The Motion Picture. Turns out that opening your mind up to a NASA probe that gained so much information it developed sentience is enough to cause agonizing pain and knock him out cold.

Literature

• In The Adventures of Tom Sawyer, Tom mentions a boy who had an incredible memory, seeming to know every verse in the Bible, until one day, the mental strain of it broke his mind.
• In the Animorphs prequel The Ellimist Chronicles, Toomin (The Ellimist) is captured by "Father", a giant squid-like alien who connects his tentacles into the brains of his victims, and thus, having a network of hundreds of minds, has ridiculous intelligence (and the faculties to handle it). After decades of Father using Toomin as his plaything, Toomin finds a way to defeat him by absorbing all the thousands of minds that Father uses... into his one brain. The strain of having so many minds meant for so many body types caused him to hallucinate. Rather than finding a way to return to normal, however, he spends years building a spaceship/supercomputer to plug himself into (and escape Father's planet), which makes him capable of handling his newfound superintelligence. He is still mostly Toomin, however.
• In Fred Hoyle's novel The Black Cloud, scientists communicating with the Cloud are given a recording of its knowledge. An initial attempt to download the knowledge into one of them proves to be quickly fatal; a second attempt seems more promising at first but also ends in mental breakdown and death.
• In the first arc of A Certain Magical Index, we are introduced to the titular character, Index Librorum Prohibitorum, a member of the English Church who has become a living database for 103,000 grimoires thanks to her Photographic Memory. Oddly enough, besides the grimoires, she only has memories of the last year of her life and believes that she is being hunted by enemies of the church. It's soon revealed that these "enemies" are actually her forgotten friends, and her excellent memory is more of a curse than a blessing. The human mind can only contain so many memories, the grimoires already put her near that limit, and she naturally gains more memories over time. If left as is, she would eventually die from the strain, the best solution her friends have been able to come up with is periodically wiping her memory. Ultimately subverted, the protagonist Touma figures out that this was all just an excuse to wipe her memories for the purpose of preventing her from developing too much independence and possibly becoming a threat.
• The Dark Profit Saga: A recurring problem for The Ageless elves, they're constantly forgetting things in order to make room for new memories, gradually becoming what is essentially a completely different elf. Kaitha claims that she's not the legendary Jade Wind who saved Gorm's grandfather, she's someone trying to be that person in between bottles.
• Discworld:
  • In Small Gods, the illiterate Brutha nevertheless has Photographic Memory. He experiences discomfort after visually memorizing the contents of an entire library. The discomfort comes from one of the recurring themes in the Discworld series: Knowledge is power. Knowledge is found in books. Therefore, libraries have immense power. And Brutha had all of one in his head, even if he could not read it.
  • While he doesn't have a brain in the biological sense, Death often finds his vast Photographic Memory to be a psychological burden. This kicks off the plot of Soul Music, where he goes AWOL to try and learn how to forget while Susan takes care of the family business.
  • Tiffany Aching briefly experiences this in The Wee Free Men, when she is "woken up" and knows everything in the Chalk from a single stalk of grass to the animals whose fossils made the pebbles. She uses it to defeat the Fairy Queen and then promptly gives it back, as no person could stay like that for long.
  • It also happens in a strange way in Feet of Clay, in which Golems are animated by a chem, or scroll inserted in the head that contains religious writing and instructions on how to behave. They create a king, and his chem is much larger and filled with instructions on how to be a king and/or messiah, many of them mutually contradictory, driving him insane.
• The Divine Comedy:
  • When listening to the ghost of a crusader sing on Mars, our 14th century poet is so overwhelmed by the divine truths the ghost sings of that his intelligence can't contain them. Thankfully, the soldier-spirit simplifies his speech so the poet's mind doesn't crack like a twig.
  • Even with Heaven's light and the Virgin Mary's intercession empowering him, Dante can't keep even a flawed memory of what God is like in his head, losing more memory of that event than memory had been lost of events from two thousand years before.
• Ender's Shadow features a very, very dark version of this trope. It is revealed about halfway in that Bean, a diminutive but fiercely intelligent kid, has been genetically augmented at birth to have an almost infinite capacity for learning, because his brain continues to grow like an infant's. His brain will never stop growing; neither will his skull, his bones, or the rest of his body. It's only a matter of time before he becomes far, far too big to support himself and one of his organs gives out. This remains a major plot point over the rest of the Shadow novels. Worse, it's discovered that Bean's genetically engineered traits are inheritable. It's estimated that any children of Bean's have a fifty-fifty chance of inheriting the genetic traits responsible for his unceasing growth. Naturally, Bean and Petra go to great lengths to prevent their children from being given the same death sentence as Bean. Equally naturally, Achilles deliberately screws with their preventative measures. At the end, it's implied that one of Bean's kids — one of the ones who inherited the genetic trait — was taken off-planet by the surrogate mother, who was under the impression that she was carrying Achilles' heir. This is later confirmed, both by Word of God and in the last book.
• Fablehaven has the Oculus, an artifact that grants sight to every location simultaneously. Kendra's only able to handle it until she starts trying to see outside the house, at which point her vision expands infinitely until she sees everything and loses all perception of herself. While the bad guys do eventually learn how to use it and there's no magic that can block it, the sheer volume of input means they can only focus on one area at a time, letting characters sense that they're being spied on and occasionally encourage them to look elsewhere during important meetings.
• In Flowers for Algernon, the titular mouse and the intellectually disabled protagonist Charlie Gordon are both given extreme intelligence from an operation. However, as time goes on, both Algernon and Charlie Gordon start to degrade in intelligence before finally dying, with any way to stop this from occurring lost when Charlie started losing his intelligence.
• In Foundation and Earth, Daneel is revealed to suffer from a bad case of this.
• The title character in Funes the Memorious by Jorge Luis Borges.
• InCryptid: In Imaginary Numbers, Sarah suffers this when she undergoes a mental metamorphosis and starts doing cosmic equations to rip a hole in reality. At the climax, she mitigates the overload and avoids melting her own brain by mentally linking to her friends and family, and then all the other Johrlac, to offload some of the equation into their minds. Most of the Johrlac don't have enough room for the information and it destroys their sense of self to make room for itself.
• In Inheritance, Galbatorix is defeated this way. Realizing that Galbatorix and his infinite amount of power would be unkillable with any number of attacks thrown at him, Eragon decided to just cast a spell that would make him understand all the pain he has caused. He Goes Mad from the Revelation. It's cooler and more epic than it sounds.
• In Kiln People, a widespread technology is the creation of "dittoes", short-lived clay-based copies of a person that share their knowledge and upload their memories into their original at the end of the day. The problem is that the human brain only has space for a few hundred years' worth of memories — ordinarily not that big a problem, since over your lifetime you'd only add maybe a century or so of memories. One character, however, has become a "queen bee" — she stays in one place and sends out dozens of dittoes at a time to live her life for her — and arranges for an elaborate suicide when she realizes she's almost out of room.
• The short story "The Last Master of Limericks" invokes this trope. The eponymous Last Master is basically a Brain in a Jar operating the defenses of the Solar System. It's kept "asleep" when not actually needed because of the trope. It muses at one point during the story that it long ago reached maximum capacity and now must continuously grow in order to have space to store new memories... fortunately (or maybe not; it's got one of those endings), it's a large jar.
• The Long Dark Tea-Time of the Soul: In a variant, Kate once read that the human brain can juggle a maximum of seven trains of thought or observation at once. Sure enough, when an eighth thought occurs to her, a plot-relevant detail she'd just begun to notice pops out of her head and is forgotten.
• Mistborn: Secret History: When Kelsier temporarily holds the power of a Piece of God, he gains its ability to see into the future through the Spiritual Realm. However, the future is made up of infinitely branching possibilities and relationships, which he can't make any sense of without the god's Super-Intelligence.
• In My Next Life as a Villainess: All Routes Lead to Doom!, bratty young Katarina bumped into the prince, fell over, and hit her head on a rock, which cut open her forehead. The injury wasn't all that serious, as Katarina herself says, but it caused something important. Namely, it caused Katarina to awake to her Past-Life Memories, which caused her brain to completely overflow and then shut down for five entire days while she remained in a coma with a high fever. When she woke up, her personality became totally different, and she realized that the world she was living in was all part of a visual novel she had played in her past life...
• My Teacher Is an Alien: In book 2 (My Teacher Fried My Brains), Duncan goes from dumb bully to super-genius after using an alien machine. However, his brain soon begins to pick up information like radio and TV signals out of the air, making it impossible for Duncan to think. Justified: it turns out that the alien's plan was to make his brain into a communication device so she could contact her leaders in space.
• The Bruce Sterling short story "Our Neural Chernobyl" is written as a review of a monograph studying the social and cultural effects on the world after an engineered virus is released that causes rampant dendritic growth — essentially, making people's brains extremely plastic and adaptive so they can constantly learn and think at faster and faster rates. It also frequently causes lethal burnout, nicknamed "chernobyling" after the Chernobyl power plant disaster. Eventually, the virus even jumps species, with some animals showing signs of increased yet distinctly inhuman intellect.
• In Radiant by James Alan Gardner, the "Balrog" hive-mind spore colony infecting Youn Sue's mind grant her wish to see and think as they do... by spreading her mind slowly to absorb more information while retaining the detail of her original perspective. She pleads for them to stop, but they continue until she blacks out from brain damage. The Balrog then moves in and reconstructs the damaged bits to bring her out of her coma.
• In Rebuild World, the Old World internet still exists, and those who aren't careful while exploring ruins might have huge chunks of it directly downloaded into their heads, causing their brains to shut down from sheer Sensory Overload. Alpha protects Akira from this by acting as a filter for it go through, preventing him from suffering its effects while also hoarding the information to herself to reveal to Akira at her discretion. In her Origins Episode, Carol discovers that she's an Old World connector in the Mihazono ruins when being overwhelmed like this, but some ghostly presence she encounters stops the damage just in time.
• The "total perspective vortex" in The Restaurant at the End of the Universe appears to do something like this; by stuffing the entire vastness of the Universe into the victim's head, their personality is squashed into a nice compact ball of insanity.
• The Secrets of the Immortal Nicholas Flamel has Gilgamesh. Yes, the Gilgamesh from the earliest written story. He has many millennia of memories, causing him to go slightly nuts and lose track of some of them; he talked with one person for five minutes before remembering he wanted to kill that person.
• In So I'm a Spider, So What?, use of powerful observation skills such as Appraisal and Detection bombards the brain with more information than it can process. Appraisal causes fierce migraines, so most people rely on tools to use the skill instead, while a split second of Detection actually damages Kumoko's soul. The only way to avoid this is by acquiring skills to supplement the brain's processing ability and Heresy resistance to protect the soul.
• StarCraft: The Dark Templar Saga has this as one of the main plot threads. Human archaeologist Jacob Ramsey gets the entire mind and consciousness of a Protoss transferred to him, except this Protoss is a Preserver, who has the memories of the entire race. This results in Jacob having several brain tumors develop, and he must find a way to get the Protoss out of his head.
• In the novella Starplex, this is the cause of one species' (the Ibs) natural death — the crystals that store their memories become full, and new memories begin overwriting their autonomic functions. Other species, once they develop immortality, eventually have to start discarding portions of their memories once they reach a certain age, though it's not clear what the side effects of not doing so would be.
• In A Study in Scarlet, Sherlock Holmes claims that the reason he is so ignorant of such things as astronomy is that he's trying to save brain-space for forensic knowledge.
• Time Enough for Love:
  • This is noted as an issue when a computer seeks to download its personality into a Wetware Body in order to experience life as a human. The computer's mentor and confidant has to remind it that it won't have nearly the same processing power or capacity for information storage, and indeed once the feat is accomplished, the now-female human Minerva discusses the choices she made in terms of which memories to discard and which to keep in order to avoid this trope.
  • The 2,200-year-old human Lazarus Long occasionally has problems with memory. He uses some hypnotic and mnemonic techniques to remove unneeded memories and index the important parts, but more than once he's woken up and started looking for a book he finished reading decades ago. When he travels through time to his childhood home, he's repeatedly shocked by what he's misremembering.
• In Touch (2017), Caspar's empathy gets overwhelming when he's around large groups, particularly at school; he usually arrives early so that he can slowly acclimate to the growing number of people arriving. Focusing on one particular person can drown out the others, though, so he has a list of pleasant minds that he likes to rotate between.
• Averted with the titular immortal of The Vampire Tapestry, who remains active for roughly one human lifespan at a time, then goes into hibernation for an undetermined period, always waking as an amnesiac.
• A character in M. John Harrison's Viriconium stories can only remember the last two centuries of his life, although evidence suggests he is far, far older. He lives in a vast underground complex full of machines he doesn't remember building — or what they do — and entire wings he forgot existed.
• Vorkosigan Saga: Barrayaran Imperial spymaster Simon Illyan was one of a host of low-ranking officers who'd had an eidetic memory chip implanted by order of the previous Emperor. Illyan was the only one not to suffer schizophrenia or worse as a result of the chip, largely by maintaining as small and pointless a personal life or personal opinions as possible. In the novel Memory, however, the chip malfunctions and makes Illyan a massive security risk as he begins spouting countless secrets whenever he's not sedated, and it is slowly killing him. After the chip is removed, his memory is now much worse than a normal person's due to having leaned on the chip's capabilities for so long.
• War With No Name: The translator gives enormous knowledge, and this is a danger for a first-time user.
• In Poul Anderson's World Without Stars, humanity has achieved near immortality, but because our brains weren't designed to hold centuries of memories, every hundred years or so, people have to go in and decide what memories they want to keep, and what they want to forget.
• In the Zachary Nixon Johnson series, a powerful psychic named Maggie Chill tries to read Zach's mind. However, since Zach is mentally linked with his A.I. assistant HARV, she ends up getting his entire computer database downloaded into her head. Zach compares it to trying to drink a glass of water and getting the entire Atlantic Ocean. The information overload knocks Maggie catatonic; HARV says that she'll survive, but will likely have a headache for weeks.

Live-Action TV

• The 4400: In "Daddy's Little Girl", Michael Ancelet developed total recall after taking promicin. He is able to remember every detail of his life in perfect accuracy. However, the memories build up to such an extent that he feels as if his head will explode if he doesn't write them down. Michael's autobiography is already hundreds of pages long, and he has only gotten to the fourth grade.
• The Amazing Stories episode "One for the Books" (based on a story by Richard Matheson) has a man involuntarily soaking up all the knowledge contained in the library in which he works, which quickly drives him towards madness. In the end, it's revealed that it was done by aliens as a way to gather all that info; they "squeeze" it out of him and go on their way.
• In Andromeda, Harper has a database downloaded into his brain (he has a computer port on his neck), and it plays out similar to Stargate SG-1, only instead of being directed to a single goal like O'Neill, Harper begins and abandons dozens of projects.
• Cordelia from Angel is given the "gift" of visions that turned out to cause her brain to slowly deteriorate since humans weren't meant to have them. She keeps it secret for years before slipping into a coma and learning that she will eventually die from this if she doesn't agree to become half demon to compensate. She is also shown other examples of what happens because of the visions: one girl whose head literally blew out the back, and an alternate-universe Angel who was driven completely insane by them.
• In the Buffy the Vampire Slayer episode "Earshot", Buffy accidentally gets telepathy and starts hearing everyone's thoughts all the time. This not only overwhelms her, but it will inevitably cause her to go crazy unless the telepathy is removed. There was one other person to have gotten this, and he ended up in complete isolation, away from any other people.
• Chuck entirely averts this until it's revealed that the reason Chuck was sent the Intersect was because he was one of the few people who wasn't immediately killed by this. After a few years, it seems to finally be hurting him. Then there's the instances where characters aside from Chuck gain the Intersect. When Morgan has it, his memories are being fried and his normal personality is being "corrupted" by it. Moreover, in the series' final Story Arc, Sarah has to upload the Intersect in order to rescue Chuck from the Big Bad, who has kidnapped him. However, much like Morgan, her memories take a hit, and she ends up losing all that she remembers of the past five years. This gives the villain a chance to use the amnesiac Sarah as a weapon of sorts against Chuck. Keep in mind that these instances involve variations of the Intersect that are tampered with via "trojan horses".
• This almost happens to Max in an episode of Dark Angel which involves her taking a rival series clone's neural implant and installing it into her own brain. The strain nearly burns out her nervous system.
• Ed Bellamy from Dead at 21 has one year to keep the intellect-enhancing chip in his brain from frying it.
• Doctor Who:
  • Russell T Davies is clearly very fond of this trope, as all of the below examples are from his tenure as showrunner.
    • "The Parting of the Ways": Rose absorbs the Time Vortex, making her effectively a goddess, but is in danger of being "burned up" by the power and whispers, "I can see everything. The sun and the moon, the day and the night — but why do they hurt? My head... is killing me."
    • As revealed in "The Sound of Drums", becoming a Time Lord runs the risk of this. The initiates are taken to the Untempered Schism, a hole in space-time, and forced to look inside at the whole of time and space. Those who aren't inspired or run away tend to go completely flipping bonkers. The Doctor suspects the Master is a result of this.
    • "Forest of the Dead": In a fatal example, River Song uses her own brain as a data buffer to download the Library survivors out of the core, killing her in the process.
    • "Journey's End": Donna Noble has all of the Doctor's mind copied into her head; combined with human ingenuity, this makes her even cleverer than the Doctor. But her mind cannot take it, and the only way to save her is to remove all memories she has of the Doctor and their adventures.
  • "The Haunting of Villa Diodati": Percy Shelley nearly dies after accidentally absorbing the Cyberium, a powerful Cyber-AI containing data on the entire history of the Cybermen, because it's too much for his brain. By contrast, the Doctor's Time Lord mind can handle it just fine.
• Firefly: River Tam got along pretty well being incredibly intelligent with a bit of psychic ability. Then the government gets a hold of her. They make her undeniably kickass, but one consequence is that now her greatly increased psychic abilities make her insane, unable to filter out what she hears.
  "Make them stop! They're everywhere. Every city, every house, every room; they're all inside me! I can hear them all and they're saying... NOTHING! GET UP! Please, get up!... Please, God, make me a stone."
• In Heroes, Matt Parkman has this problem when he gets his telepathy, but after a while he learns to control it better and the problems stop... until Ando super-charges Matt's power, causing a temporary but disabling case of this trope.
• In one episode of The Invisible Man, Hobbes is accidentally stabbed with a serum that causes his intelligence to rapidly increase. However, he will go through several stages, gradually becoming an Insufferable Genius, then a crazy genius, then, with this trope, his brain will become so advanced that he will retreat into his own mental world of absolute knowledge, and stop using or caring about his body at all. One of the college students who was injected committed suicide and took the creator of the serum with her; the other three ended up catatonic. Fortunately, it's stopped and reversed at the Insufferable Genius stage.
• In one episode of Joan of Arcadia, a child who Joan had babysat earlier in the season dies. In the middle of a Rage Against the Heavens rant at God, God offers to show her what he sees and hears every day. Fifteen seconds later, she's on the floor, unable to deal with the downsides of omniscience.
• In Married... with Children, Kelly Bundy goes on a tv trivia game show on the subject of sports. Her father Al and brother Bud teach her quite a lot of trivia, but they're careful because they know that if her brain gets full then something she already knows will fall out. Unfortunately, when she appears on the show, she "learns" something new and sure enough, the audience hears a "ping" as an old piece of knowledge falls out of her brain. Come the $1,000,000 question and Kelly doesn't know the answer. The question: Who once scored four touchdowns in a single game for Polk High School in Chicago? The answer: Al Bundy.
• The Outer Limits (1995): In "Stream of Consciousness", the Stream forces people to collate all information in the world to the point that their brains cannot process it and they die.
• Red Dwarf
  • In "Holoship", Rimmer has all the knowledge and experience of two officers of the ship transferred into his own mind so as to pass an exam. Kryten warns him, however, that it could "reduce him to a gibbering wreck". It doesn't, and the result is slightly unnerving.
  • In "White Hole", the ship's computer Holly finds a way to boost her intelligence and undo three million years of "computer senility". Overclocking it, she gets an IQ of 12,368 (over her original IQ of 6,000) at the cost of reduced run-time: about 3 and a half minutes.
• In The Second Coming, Steve discovers that he's literally the son of God. He compares the experience of accessing divine omniscience with a human brain to "downloading fifty-million megabits into a pocket calculator", and though it doesn't seem to be actually dangerous, he admits that it hurts.
• The Stargate-verse has used this a few times:
  • In Stargate SG-1, there are Ancient Repositories, where if you stick your head in you get all the (possibly nearly infinite) knowledge of the Ancients, but a human mind will slowly degrade for as long as the information is still in there. Jack O'Neill got nailed twice by those devices, but was fortunately able to access enough information to work out how to contact the Asgard and have them remove the data. The Asgard were actually impressed by this: they'd previously assumed that human minds weren't advanced enough to do even that much, and that any human who tried would simply die.
  • Also in Stargate SG-1, Orlin, an ascended Ancient, takes a human body in order to help the main characters with the current Big Bad. Unfortunately, he holds onto the necessary knowledge for too long; he ends up suffering massive brain damage, and has to be institutionalized.
  • When RepliCarter tried to download that same ascended knowledge using the formerly ascended Daniel's brain as a conduit, she was confident that the combined storage space of the Replicators would be sufficient to contain it. She was wrong: the combined memory of all Replicators was insufficient to hold it all, and they begin to lag under the strain of trying. Nothing bad happened specifically because of it, but the distraction was enough for Daniel to get the better of her and seize control of the Replicators for a few minutes.
  • In Stargate Atlantis, a hyper-evolution machine gives Rodney McKay amazing mental powers (including psychic ones such as mind reading and telekinesis) — but at the cost of it eventually killing off the part of his brain that controls the lower functions, such as his heartbeat. It's at the last moment of his life that he manages to figure out (using his amazing intellect) how to reverse the process to return to normal.
• Star Trek: The Next Generation:
  • Done with Data's daughter Lal in "The Offspring". First, she's able to use contractions. Then, she gets actual human emotions. Unfortunately her body cannot deal with this and she shuts down permanently.
  • In "Sarek", Sarek's illness causes his impulses to project onto others around him, leading to the crew of the Enterprise to become testy, if not outright violent, with each other.
  • Lt. Barclay in "The Nth Degree", although the newly gained super-intelligence doesn't seem to be dangerous in itself. The problem comes when he connects his brain directly to the ship's computer. He uploads himself and uses the extra processing power to expand his intelligence, but then realizes that his brain alone would be too small to contain it, so he's stuck in the computer until the end of the episode—at which point, the Cytherians (who had sent the probe that zapped Barclay) removed most of the extra intelligence, though Barclay did seem to end the episode with a slight—but noticeable—permanent boost to his intellect.
• Star Trek: Voyager:
  • In "Darkling", the Doctor uploads the knowledge of many geniuses into himself, but he also ends up getting their dark sides too, which turns him into a Mad Doctor.
  • In "The Voyager Conspiracy", Seven of Nine downloads huge amounts of data straight into her head, but can't handle it, and starts creating wild conspiracy theories. The scary thing is how much sense most of them make, given the evidence she provides, until she starts using the exact same evidence to create different, contradictory theories.
• Tales from the Darkside: In "The Bitterest Pill", a man invents a pill that allows for knowledge to be gained and stored at an alarming rate when taken, the only side-effect being an agonizing headache. He tries to convince his friends (a married couple who are neglectful and dismissive of their only son) to invest in the production of the pill but while the conversation is taking place, the child takes a few of the pills and even comments that they taste delicious on top of everything else. In the next scene he is shown to have become emancipated from his parents as well as the CEO of a company that produces the pill. In the last few moments of the episode, he speaks of the initial inventor's mistake and says that the inventor never realized that his pill worked best on a mind that was still developing rather than a fully grown one adding that the inventor's mind overloaded and couldn't take the massive influx of information.

Roleplay

• Dawn of a New Age: Oldport Blues:
  • When Finn first receives his power of psychometry, he picks up an immense amount of information on his immediate surroundings and temporarily suffers a spasm until the effect wears off.
  • Benedict's power grants him a hyper-intelligent mind, with the downside being that he can never turn it off and is always hyper-aware of every minute detail at every moment. In particularly stressful situations, such as when Carlie is shot, the information overwhelms him and leaves him paralysed.
• In We Are All Pokémon Trainers, the reaction of gaining two sets of memories from the Alternate Timeline and the original is a temporary brain overload.

Tabletop Games

• Dungeons & Dragons: Downplayed with the Detect Thoughts spell, which shorts out and delivers a temporarily incapacitating Poke in the Third Eye if the caster attempts to read the mind of a creature with Super-Intelligence.
• The Warforged from Eberron regularly have old memories deleted in order to avoid this problem. However, the deletion process isn't perfect; as such, Warforged can always make Knowledge checks even if they don't have the requisite skill (something normally not allowed by the rules), representing them touching on a half-erased memory of the subject.
• Several cards in Magic: The Gathering provide extra draws (and thus, potentially knowledge of additional spells in-game) at the expense of life points, making overuse of them naturally dangerous. And not all of them can be easily "turned off" once in play...
  • The other danger of excessive card drawing is that you lose the game if you have to draw from an empty deck. There are several tournament strategies that involve generating obscene amounts of mana, then dropping a Stroke of Genius or similar card to make an opponent draw their entire deck plus one card.
  • Also, the hand size limit may be a less lethal example of the trope. A player can technically end up with any number of cards in his or her hand for a time... but at the end of his or her turn, he or she has to discard any in excess of his or her current maximum hand size (which usually starts at seven and stays there unless modified by specific effects), presumably reflecting how much arcane knowledge his notional brain can safely hold for long.
  • In a more narrative use of this trope, many cards equate drawing cards to gaining knowledge, and thus equate drawing at a cost with this trope. The various Innistrad series, in particular, have several cards which involve drawing and discarding or exiling cards, with the flavor being that the user gained too much knowledge that one is not meant to know and subsequently went insane, or was forced to expunge prior knowledge.
  • The card Rush of Knowledge mentions this; "Limitless power is glorious until you gain limitless understanding", the picture shows a mage receiving knowledge, much to his discomfort.
• In Warhammer, Festus the Leechlord was once a doctor who was attempting to cure a plague ravaging a village and in a moment of desperation accepted an offer from Nurgle (God of Disease) for the information necessary to cure all diseases. What he got was knowledge of all disease in existence loaded into his brain all at once, which drove him mad and turned him from a well-meaning healer to a Champion of Nurgle seeking to spread disease across the world.

Video Games

• It has become an open secret that that Arakune of BlazBlue Was Once a Man, but a good portion of his dementia comes from a Runneth Overing Skull. He acquired so much knowledge that his mind began dumping random parts of his psyche, and the process is ongoing. Of course, that means the knowledge he possesses about everything — including himself — is essentially random at all times. This makes all the attempts to save him with The Power of Love more tragic.
• In Bloodborne, this is the typical outcome of would-be Godhood Seekers beseeching the Great Ones to bestow their knowledge of the cosmos on them. To wit:
  • Rom was able to successfully become a Kin of the Great Ones through contact with Kos, but the process burned out her mind and reduced her to the level of a giant bug with cosmic power.
  • Provost Willem of Byrgenwerth College tried to "line his brain with eyes" using a piece of Great One umbilical cord, but the ritual seems to have functionally had the opposite effect: by the events of the game he's a drooling vegetable, unable to rise from his rocking chair as he blankly gazes out upon Moonside Lake, where Rom resides.
  • The School of Mensis made contact with Mergo in an attempt to bargain with the stillborn godling for eldritch knowledge, but all they got out of it was "the stillbirth of their brains". The entire lot of them are long dead by the time you enter their ritual chamber in Yahar'gul, nothing remaining but skeletons. They seem to still be alive in the Dream Land, though almost all of them, the most prominent exception being their leader Micolash, seem to have degenerated into various monsters.
• Devil Survivor: Downplayed with Cain, a.k.a. Naoya. On the up side, living forever has given him an uncanny exploitative insight into human nature and motivation so complete that he can accurately predict an entire city's future (barring a Screw Destiny maneuver, of course). On the not-so-upside, his immortality and perfect memory have left him unable to relate to most people and give him deep frustration at seeing history's mistakes repeated constantly.
• In Disco Elysium, the player has the option to invest skill points in the Encyclopedia skill, which will allow the Player Character to remember trivia and facts about the somewhat strange Urban Fantasy world he inhabits and bring them up in conversations. There is a downside, however, to investing too many points in this skill, namely that the voice the skill manifests as in the Player Character's head will keep interrupting his trains of thought by talking about trivia and titbits constantly, which may be distracting or even disorienting.
• In The Elder Scrolls, the Ayleids ("Wild Elves") were Abusive Precursors who enslaved Cyrodiil's native Nedic people, ancestors of most of the modern races of Men in Tamriel. Like their Welkynd and Varla stones, the Ayleids possessed crystals which could release memories directly to the user. Overuse of these crystals was said to cause a "problem of capacity" for mortal minds.
• Final Fantasy XIII-2: Serah and Yeul will experience a vision of the future every time the timeline is changed by resolving or causing paradoxes. While that may sound alright, each vision affects them worse and worse (it begins as a small migraine, and eventually causes them to faint each time) until they eventually keel over and die.
• In Mass Effect, the Prothean Beacons were designed to easily transfer information across their Empire. However, because no other race possesses the Protheans' natural empathic abilities, viewing them can potentially run the risk of destroying a weak-willed individual's mind entirely.
• In Metroid Prime: Hunters, the bounty hunter Kanden was given extensive combat encoding, but the information was more than he could handle, and the process drove him insane.
• In Plague Inc., the Simian Flu has a group of symptoms that at first glance seem counterproductive: Neuro-Enchacement, which causes the intelligence of humans to increase, making them faster at developing a cure for your disease... at least, the first 3 tiers of the symptom do. The fourth tier ensures that the neuronal growth (and, more importantly, the DNA alterations that cause it) triggers a massive autoimmune response that ends up being utterly lethal to the host, making it the deadliest symptom in the Simian Flu.
• The Secret World: In simple terms, the Big Bad Lilith used to be a human, but apprenticed under an Arc-Angel, who shared his knowledge with her and had to then modify her genetic code so her brain could handle knowledge that mankind was not meant to know. Even with her restructured brain/genetic code, the woman became a Mood-Swinger, just internalizing all she is now. She can comprehend the secrets of the cosmos, but frequently forgets who she is at any exact moment.
• Star Wars: The Old Republic: Consular companion Felix Iresso and another soldier were captured by Imperials and had Sith holocrons forcibly downloaded into their heads. Sith holocrons are bad enough news, as they corrupt Force Sensitives, but Felix and his pal weren't. They can't willingly access the information, and Felix's buddy went insane after the information surfaced. Unfortunately for Felix, there doesn't seem to be a cure, so he's left with a ticking time bomb in his head.
• Wizardry:
  • In Wizardry VI: Bane of the Cosmic Forge, one NPC is a moderately evil wizard who wished on the Cosmic Forge that "I shall know everything." The artifact's solution to the trope was to split him into two consciousnesses and divide the knowledge between them. However, as it chose to concentrate data in the one that got the body, he went insane anyway. The one who got the understanding (the "hows" and "whys") relates the story to your party.
  • In Wizardry 8, this can happen to your own party. One of MacGuffins necessary to complete the game is Destinae Dominus, the key to knowledge. If it is held by member not wearing Helm of Serenity, everyone in the party will become insane.

Webcomics

• In El Goonish Shive, extended psychic conversations with the "whale" is implied to result in this given one that lasts less than 1 second results in a nasty headache.
• Homestuck: Sollux is a high-level psionic. The mind honey which boosts his lusus from idiocy completely overloads his brain when he eats it.^note YOU DO NOT UNDER ANY CIRCUMSTANCE EAT THE MIND HONEY. He recovers, but there are terrible consequences.
• In Kill Six Billion Demons, the God Empress Jadis forced herself to witness the True Shape of the Universe, a feat that once caused a goddess' eyes to boil in their sockets. This made her The Omniscient but scoured her body and mind, leaving her a Dark Lord on Life Support who can do nothing but whisper infallible prophecies from the block of glass in which she's entombed. As it turns out, she's still perfectly lucid in there (at least, capable of pantomiming perfect lucidity), simply utterly crushed by the knowledge that the future is deterministic and unchangeable.
• Mindmistress:
  • Mindmistress gets her super-intelligence from a Phlebotinum pulse that kills the target in two weeks unless reversed (the brain grows so much that it is analogous to brain cancer). Her non-super self is mentally challenged.
  • Also used in a different way in a later story when the villains of the week attempt to steal her knowledge. They all go insane — the human mind cannot handle that much knowledge.
  • Forthought is an ordinary man who underwent the same process. He is considerably smarter than MM and with his more advanced mental capacity he wills his brain to not have cancer rather than transform back.
• In Schlock Mercenary, a race of immortal aliens are found on a backworld planet. The collapse of the civilization nearly a million years ago was due to their experiments with immortality, leading to this trope as many of them went insane due to too many days going by too similar for the mind to sort out. Amongst the many measures they tried, only one worked — upgrade their brains to make them controllably forget or ignore vast swathes of their memories.

Web Originals

• Captain's Log has a group of aliens with nanomachines that make them immortal and heal them from all injury. The problem is that, during the 300-year journey to Earth, their brains proceed to run out of room, inflicting all of them with anterograde amnesia (the inability to form new memories). This is why Aliens Abduct Cattle — from their perspective, they're always collecting their "first" sample.
• Dungeon Life: When Thedeim turns one of his creatures into a Voice so as to communicate with others, that connects the Voice to his own mind — which means that if Thedeim thinks too much about his previous life, the Voice gets glimpses of all sorts of advanced concepts from geosynchronous satellites to quantum superposition, quickly resulting in a headache.
• During the Happy Hour arc of I'm a Marvel... And I'm a DC, an Exposition Beam is weaponized to do this on a small scale.
• In Season 5 of The Magnus Archives, the Archivist gains the ability to do this, forcing avatars of the Powers to know and understand all of the pain and horror they had inflicted on their victims, destroying them.
  "Ceaseless Watcher, turn your gaze upon this wretched thing."
• SCP Foundation:
  • Apparently, this is what happen to humans coming in contact with the mysterious being SCP-606, resulting in coma and death from overload of information. The entity doesn't seem to do it out of malice, instead calling it "enlightening" its victims.
  • SCP-028 can also overwhelm an unprepared person.
  • Class W mnestics are drugs which provide resistance to many forms of Laser-Guided Amnesia and Perception Filters. Class Z mnestics permanently destroy the brain's ability to forget anything or filter out any perception, providing complete immunity to all forms of Laser-Guided Amnesia and Perception Filters. Unfortunately, the human brain normally filters out the vast majority of what sensory neurons perceive and normally forgets most things. Anyone who takes a class Z will recall, with perfect clarity, every instant of every single sensory neuron pumping information into their brain, leading to death by seizure in an hour or two.
• This is the outcome of Project Caterpillar in Twig, as Jamie's Photographic Memory produces too much information and he fails to pull himself together after an appointment, leading to a Death of Personality.
• At the end of Worm, Taylor has Panacea jailbreak her power, giving her the ability to control every bug and parahuman in a 16-foot radius. Once she gets ahold of some more powerful capes, she quickly assembles a massive army to take on Scion, the world-destroying alien entity responsible for all the powers in the first place. However, with her power operating at peak capacity she begins losing her ability to speak, or understand language at all. After that, she forgets her friends' names and how to relate to anyone outside of any context besides war and conflict. She gets better, fortunately.

Western Animation

• The Adventures of Jimmy Neutron, Boy Genius: In "Sheen's Brain", Sheen, who is somewhere between The Ditz and a Cloudcuckoolander, is hit with Jimmy's brain-gain helmet, without fixing the issue of the original brain-drain helmet, a limiter. At first, it just results in incredible intelligence and a much larger head, but after a while, Sheen develops outstanding Psychic Powers, a god complex, and a head the size of a house before the Reset Button is hit. It's mentioned that if the growth isn't stopped, Sheen's head will eventually explode. At one point, Jimmy calculates the maximum possible number Sheen's IQ could grow to. It hits infinity.
• The Batman:
  • Minor example with Edward Nigma, as it wasn't enough to outright destroy his mind but enough to mess things up in a big way. He was originally a scientist who, along with his partner, invented a device that when worn on the head bolsters one's cognitive ability. During a demonstration it is sabotaged however, rendering him permanently brain-damaged and turning him into The Riddler who's obsessed with crime and revenge.
  • Dr. Hugo Strange gets all the knowledge in the universe in return for helping the Joining. When he receives it, he ends up comatose (though the Martian Manhunter can still read his mind to get the information they need to defeat the Joining).
• Code Lyoko: Jérémie once tried to use the same quantum memory technology that powered the Supercomputer to enhance his own brainpower. Of course, it backfired due to both the immense physical strain and the fact that XANA introduced the possibility of that maneuver as a Red Herring.
• This is used against a villain in one episode of Darkwing Duck. In the final showdown, DW and Launchpad get their hands on the Norma Ray, a device that increases your IQ and gives you psychic powers as long as you clear your mind of all thought (or else you get a literal and figurative "swelled head"). They bombard the villain with rays while asking him a bunch of tough questions at once, causing him to lose his concentration and make his head so big that it blows up.
• DuckTales (2017): In "New Gods on the Block!", the kids try out to be Zeus's replacement in the Greek pantheon. Huey's audition as the God of Intuition backfires when his ability to see people's futures leads to him upsetting people by blurting out their worst possible futures, not to mention making his head swell to grotesque proportions.
  Huey: I can never know that much again!
• In Freakazoid!, this is the entire reason why the titular superhero is so damn zany: the accident that empowered Dexter also uploaded all information from the Internet into his brain. Maybe that wasn't that big of a deal back then, considering the volume of info had yet to reach the terabytes (perhaps even gigabytes), but even at that time, that was still a lot for a single brain to handle... though it could also have to do with what all the information from the Internet encompasses...
• In the Justice League story "Paradise Lost", Felix Faust makes a bargain with Hades for ultimate knowledge; when Hades gives it to him, Faust cries in pain and begins to shrivel and wither, making it seem like this trope is in effect. Subverted; Hades then tells him that "Ultimately, pain and suffering are all mankind will ever know," making it seem more like a cruelly poetic version of Rewarded as a Traitor Deserves than this trope.
• In an episode of Men in Black: The Series, aliens bring to Earth a "Cerebral Accelerator" that boosts human intelligence. Agent J tries it on before MiB has a chance to safety-test it for side-effects and learns the device gives him Ripple-Effect-Proof Memory (which proves very convenient, since it happens at the same time that someone tries to pull a Ret-Gone on the entire MiB organization) but will eventually make his head a splode. After foiling the plot, and just before he burns out, he uses the time-travel tech to tell his startled past self, "Don't touch that!"
• In The Simpsons, Homer believes that mundane learning has this effect on him, citing as an example a time when he took a home wine-making course and forgot how to drive. Marge points out the more obvious cause of this loss of ability.
  Marge: That's because you were drunk!
  Homer: And how!
• Happens to SpongeBob SquarePants, of all people, in the episode "Squilliam Returns". Squidward turns the Krusty Krab into a fine dining establishment to impress Squilliam, and SpongeBob is to wait tables. After learning everything associated with fine dining, his skull runneth over hard, to the point where he cannot even remember his own name anymore! The only thing he can remember, except for fine dining, is breathing.
• Bulkhead of Transformers: Prime, after getting the Cybertronian data cylinder's contents uploaded into his brain becomes much smarter, but the influx of knowledge threatens to erase his memories and override his original personality.
• In Xiaolin Showdown, using the Shen Gong Wu named Fountain of Hui grants the user insight to anything and everything. However, without its sister-Wu the Eagle Scope, which is mostly an uber-telescope, the Fountain of Hui will only grant the user a humongous head and random facts, such as the length of the world's largest toenail, which they will babble incessantly for about a week. It also seems to imply that using the Fountain of Hui without the Eagle Scope results in pain as well as the huge head and random fact-spouting, given that Omi's immediate action after saying the length of the world's largest toenail is to grip his head and complain "Ow..."
• In X-Men: Evolution, Rogue's power absorption eventually leaves her with fragments of all the people she's absorbed, such that she can't help randomly using their powers occasionally. Then she goes and bumps into Mystique, providing a handy outlet for those fragments in the form of shapeshifting. A rampage ensues. Xavier has to telepathically purge her of all the accumulated personalities to get her back under control.

Real Life

• People with bipolar disorder often go through a period of high creativity, fast and often quite clever thinking before the sleep-deprivation psychosis kicks in. The feeling of being on such a high can often be like one's skull literally overflowing with energy; and sleep deprivation doesn't need to happen. The insomnia can be controlled with medication, for a start, while with proper intervention, the highs can be trained to be put to good use.
• Also people with Eidetic Memory can set off a memory at any time by some random thing, be it good or bad. As mentioned in one example under Real Life of Blessed with Suck, in extreme cases this may even end up fatal.
• Subverted by people who have suffered the loss of a substantial portion of their brains, due to strokes, tumors, accidents or surgery, yet continue to function and accumulate memories normally throughout their lives. Even patients who have entire cerebral hemispheres removed to halt their epileptic seizures don't "run out" of memory-space, despite having only 50% storage capacity.
• Some autistic people, referred to as 'savants', may have abilities that are considered superhuman: extremely good memory, fast and accurate computation in their heads, etc.
  • On the negative side, this trope can cause meltdowns for autistic people and those with sensory processing disorders. So you can sense/hear/feel, etc. more than others? Sounds cool, until your brain can't cope with an overwhelming amount/intensity of information — loud music, bright lights, intense smells, etc. This can cause distress, interfere with brain functions, ranging from discomfort, emotional shutdowns, and a need to get away from the stressor, to a full-blown crying/screaming meltdown (that are distinct from tantrums, because the person can't immediately stop the meltdown, and aren't doing it to get what they want). Many autistic individuals cope with this stress by stimming^note short for "self-stimulating behavior", basically anything that helps people calm and ground themselves: clicking a pen, fiddling with a cube, chewing on things, etc.. While this is typically benign, it's also highly stigmatized, which can invite mockery if it takes a socially unacceptable form, and in more extreme cases it can involve self-injurious behaviors.
• Solomon Shereshevskii, a Russian mnemotist (who did not, in fact, have an Eidetic Memory) had the ability to remember things so well that he became dislocated in time; he eventually became unable to tell whether the thing you just told him happened 5 minutes or 5 years ago. He had to literally learn to mentally remove facts from his memory (in other words, deliberately forget). It didn't help that he had fivefold synaesthesia, an extremely strong form of synaesthesia in which stimulating one sense meant a reaction from them all. Wikipedia has an article on him.
• Some types of DDoS (Distributed Denial-of-Service) attacks are the computer equivalent of this trope, with the server(s) being deluged with information or requests for same, beyond their capacity to keep up.
• Speaking of computers, overclocking or improperly cooling a CPU can result in the thing overheating and burning out.
• A developing problem as human longevity increases is being able to form new memories. As memories are stored in the physical structure of the brain, the possibility of simply running out of space is a strong one. Many Transhuman thinkers are proposing theoretical solutions to this problem, including artificially expanding memory via cybernetics.
• Graham's number is an extremely large number, so large that it can't even be represented in the observable universe. Simply knowing all of it will cause your head to implode into a Black Hole!

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