When you're a brain in a tank, you've got a lot of time to think about stuff. And one of the things you ponder is: how many kinds of disembodied brains does science fiction have? The answer: six!
And yes, we're only doing this list because Chip Overclock demanded it.
Evil overlords of braininess:
The Gamesters of Triskelion from Star Trek: I'm willing to bet dollars to quatloos that you've already appreciated this classic tale of gambling addicts who have itchy betting fingers despite not having fingers. If not, then this trailer is all you really need to know.
Mother Brain in Metroid In this NES classic, the boss of the game was giant, disembodied glob of grey matter surrounded by a futuristic security system. If feminist gaming pioneer Samus Aran ran out of missiles, there was no way to beat Mother Brain. The whole "running out of a common item at the final boss of the game" spiel was an infuriating conundrum typical of early Nintendo games.
Brain from Doom Patrol. This brilliant scientist was caught in an explosion which reduced him to a brain, and nothing else. Luckily, Monsieur Mallah, the gorilla he'd uplifted to genius intelligence, loved him and kept him alive inside a tank. Niles Caulder, the scientist who engineered the explosion, later transferred race-car driver Cliff Steele's brain into the robot body he'd built for Brain.
Disembodied brain develops psychic powers:
Donovan's Brain by Curt Siomak, and the 1953 movie of the same title, are about an evil millionaire whose brain is put in a vat, and then he develops mental powers, allowing him to control those around him. The movie co-starred Nancy Davis, the future Nancy Reagan.
The Outer Limits, "The Brain Of Colonel Barham" Mea culpa — I wrongly put this one into "robot bodies you can load your brain into" — but it fits way better here. Colonel Barham, an astronaut, volunteers to have his brain loaded into a robot body so he can go to Mars, but then he goes nuts and develops evil psychic powers and controls people with his mind:
Marvel What If, "What If The Fantastic Four Had Gained Different Powers?" In this "what if" tale, instead of getting stretchy-limb powers, the FF's Reed Richards becomes a super-smart disembodied brain, with mental powers. "I promise I will never dominate your brain again," he promises Ben Grimm.
The brain that cheated death:
They Saved Hitler's Brain! You only think Hitler died at the end of World War II — in fact (wait for it), they saved his brain!
"William And Mary" by Roald Dahl. William dies of cancer, but he has his brain preserved inside a machine that can keep him alive for 200 years. His wife, Mary, considers taking him home — but only so she can smoke in front of him and watch television, two things he hates seeing her do. This story was made into an episode of the Tales Of The Unexpected TV series.
Packaged for space travel:
The Mi-Go in Lovecraft's Cthulhu mythos are fungoid, crustacean extraterrestrials, who transport humans from Earth to Pluto, by removing your brain and putting it in a "brain cylinder."
Operating cities or spaceships:
Spock's Brain from Star Trek is probably the most famous example of this trope — what is brain? Brain is the ultimate city infrastructure planner! (Sexy babes steal Spock's brain and use it to run their city. It makes total sense.)
The Ship Who Sang by Anne McCaffrey is all about a girl whose physically disabled so she's put in life support to help run complex systems, and when she hits adolescence, her brain is removed and she becomes the "mind" of a spaceship — until she falls in love. Aw.
Neon Genesis Evangelion's MAGI computer system is run by disembodied human brains.
Tin Man: In this Syfy reimagining of the Wizard Of Oz, the Wizard turns out to be the disembodied brain of the Scarecrow's counterpart, and it runs a doomsday device. (Thanks, TVTropes!)
RoboCop 2: The second RoboCop is really just the brain of a psychopath, transplanted into a robot body. Which works out great!
Krang from Teenage Mutant Ninja Turtles sort of fits this one as well — he gets reduced to just a brain-like entity, and then his ally Shredder builds him a humanoid exo-suit, with his disembodied brain-creature in the tummy. Mmmm tummy brain...
"Becalmed In Hell" by Larry Niven. In this story in the "Known Space" series, the injured Eric's brain is used as the computer of a ship exploring Venus, using the empty fuel tank as a dirigible. When it's time to return to Earth, Eric announces there's a problem, and they have to land. But the "normal" human astronaut, Howie, decides the problem is actually with Eric himself.
Random weird disembodied brain:
L'oncle Irvin ("Uncle Irvin") in City of Lost Children featured a talking brain in a tank named . He suffered from migraine headaches, and spouted pearls of wisdom throughout the film.
The Harlem Heroes in 2000 A.D. are a basketball team one of whose members gets destroyed, except for his brain, which is — you guessed it — in a jar. And he still gets to stay on the team.
The Curious Dr. Humpp is a random disembodied genius brain, who can only survive as long as his acolyte siphons off the sexual energy from hot young men and women, and beams these orgones into his cerebellum. We featured a clip here.
Mother Brain in Captain N: The Game Master This Saturday morning cartoon show. She was voiced by Levi Stubbs, better known as the voice of Audrey the carnivorous plant from Little Shop of Horrors.
Star Wars features the B'omarr monks, whose brains live in jars, but sometimes spider droids carry them around, and you can just glimpse them in Jabba's palace if you squint like a Hutt.
Ghost In The Shell features many characters who've kept their organic brains but scrapped everything else. And according to TVTropes, this is a common motif in Dragonball, Kara No Kyoukai, Appleseed, Captain Future and Tengen Toppa Gurren Lagan as well.
Additional reporting by Cyriaque Lamar.