Head Transplantation

Okay, your body got trashed in a nasty accident, yet your brain is still just fine. Unfortunately though, you're facing the rest of your life in a wheelchair as a quadriplegic at best -- and that's only if you survive. But wait a minute, there's a way to fix that: just get a new body. No need to worry, the doctors have figured out how to reconnect the spinal cord, so you can walk and live on again. Neat... right?

Maybe... and maybe not.

Okay, so in real life, the idea of a head transplant is a far way off, at least in humans. Yet, that hasn't stopped some from trying, with mixed but disturbingly positive results. Of course, even if a head or brain transplant is possible and practical, there are still substantial ethical issues involved: normally, a donor body can save and/or improve the lives of eight or more people, depending on how many of its organs and tissues are suitable for transplantation; is it fair or proper to deny so many potential recipients so that only one other can benefit?

Despite the name, this trope covers transplantation of the brain alone, as well as the entire head.

This is a classic trope in works featuring a Mad Scientist.

Anime and Manga

 * Jojo's Bizarre Adventure has Dio Brando had his head transplanted on the body of Jonathan Joestar.

Comic Books

 * Marvel has Arthur Nagan, who had his head transplanted onto a gorilla's body.

Fan Works

 * In the Spice Girls AU Real Person Fic, Just Taken, one of Melanie's neighbors, Linn, had her brain transplanted into the body of a wolf after an accident. Fortunately, Linn is still treated like sa human being.

Film

 * The Thing with Two Heads has a plot about a dying white man being gained his request to have his head transplanted to a new body. Despite the man's blatant prejudice, his head was grafted onto the body of a black prisoner, who opts to be a test subject in exchange for a pardon.
 * In Mars Attacks!, Nathalie Lake and Professor Kessler both find their heads in places where they shouldn't belong, thanks to the Martians -- Nathalie and her dog exchange bodies, and Kessler's head simply goes solo.
 * The Brain That Wouldn't Die features a scientist keeping his girlfriend's head alive so he can transplant onto another body.
 * Frankenhooker, a grief-stricken former medical student goes on a killing spree to assemble body parts to create one for his fiancee after a freak lawnmower accident decapitates her.
 * Froderick Frahnkensteen Frederick Frankenstein sends Eyegor Igor to retrieve a brain of a genius to implant in his creature in Young Frankenstein. We all know how well that turned out...

Literature

 * The Airhead Series by Meg Cabot is about a brainy tomboy who suffers a devastating accident which results in her brain being transplanted into the body of a vapid party girl supermodel.
 * In I Will Fear No Evil by Robert A. Heinlein, an obscenely rich old man has his brain transplanted into a younger body. To be honest, he did it as a fancy form of suicide, never expecting it to work.  But it did, and to his horror the compatible donor body was that of a young woman he knew.  Complicating things beyond that, she doesn't seem to have left her body -- either her soul remains in her body and is advising him, or he's suffering an extensive delusion to that effect...

Music

 * In Jonathan Coulton's "Skullcrusher Mountain", the point-of-view character recounts how he made a half-pony/half-monkey monster to please the girl he's abducted. It's not explained how it all went together, but presumably the head of one was connected in some way to the body of the other.

Newspaper Comics

 * For a while in the 2000s, Bloom County had Donald Trump's brain transplanted into Bill the Cat.

Video Games

 * Wolfenstein II: The New Colossus: Set has a pet cat-monkey hybrid, Shoshana, he created by transplanting the cat's head onto a monkey's body in order her life from cancer. Unfortunately for the Nazis, this also works on humans.
 * Surgeon Simulator 2013 has brain transplants as part of the game.
 * In a Halloween Team Fortress 2 comic, the Medic, with some assistance from the Engineer, transplanted the living brain of a mugger into a jack-o-lantern. The criminal can only remain alive if his brain isn't removed from the Halloween decoration.

Western Animation
""Now be a cooperative little bunny and let me have your brain.""
 * In the second The Simpsons "Treehouse of Horror", Mr. Brain has his head attached to Homer's body after a freak accident with a robot.
 * In the episode "Put Your Head on My Shoulder" from Futurama, Fry has his head transplanted to Amy's body after an accident nearly kills him.
 * In the classic Looney Tunes cartoon Water, Water Every Hare, the unnamed Mad Scientist wants Bugs Bunny's brain to complete the creation of a giant robot.

Real Life

 * Vladimir Demikhov, a Soviet-era Russian scientist, is known for (among other accomplishments) his dog head transplant experiments in the 1950s.
 * Inspired by Demikhov, Dr. Robert White successfully transplanted the head of one monkey onto the body of another in 1970; although paralyzed from the neck down because of the transplant, the resulting hybrid survived nine days before immune rejection killed it. While it lived, though, the monkey could still hear, smell, taste, eat and follow objects with its eyes.  During the 1990s, White planned to perform the same operation on humans and practiced on corpses at a mortuary. It was hoped he could do head transplant surgery on physicist Stephen Hawking and actor Christopher Reeve.  Although his work has been dismissed as "barbaric", it has led to serious discussion of the feasibility of spinal cord reconstruction and cephalo-spinal linkage in humans as recently as 2014.