Qui-Gon: You're going to need better stats. I'm transferring some of my mini-chlorines to your blood.
Anakin: A blood transfusion? What?!
Qui-Gon: They'll multiply there and grant you lightning fast reflexes and skill points in driving.
Anakin: That's crazy!
John has one or more superpowers of the genetic and/or magical variety. He may have gained them from birth thanks to Superpowerful Genetics, genetic experimentation, or after conception thanks to Super Serum, a Mass Super-Empowering Event or a Disposable Superhero Maker. Alternately, he has mystic powers in a setting where The Power of Blood and Blood Magic are very real, so his blood contains a measure of his magic. In short, his powers course through his blood in a very real sense.
Suddenly, his friend Jack gets shot by one of his enemies, and has only minutes to live before even his copious blood supply runs out! Just by luck, Jack and John are the same blood type, and a quick emergency transfusion ensues... which results in an Emergency Transformation. Thanks to the blood-borne nature of John's powers, Jack now has those same abilities! They might be temporary and last only as long as John's blood is in his system, or they may trigger a similar reaction in Jack's body and give him permanent (and potentially different) powers.
It bears mentioning that in Real Life blood transfusions in no way transfer the donor's genes into the recipient's DNA. The red and white blood cells last only a few months before dying without leaving a trace. If John's powers are biological/genetic/chemical in nature, and/or Applied Phlebotinum is involved, Jack getting these powers is often justified by The Professor explaining that the donation triggered dormant super-genes in Jack, or actually did somehow overwrite parts of his genome. If John's powers are magical in nature, then the reason Jack gets similar powers may have to do with Blood Magic. In these cases "John" might not even be the same species as Jack, such as dragon or vampire blood note , endowing the imbiber with power. If John's powers are from a (symbiotic) virus then it reasonably would be able to transfer via blood transfusion, though you can probably count characters with these powers on one hand.
- In Blood+ Chiropteran Chevaliers are produced by draining a human male's blood and giving him a bit of a Queen's blood. Both of Saya's Chevaliers were created by Emergency Transformation of someone she cared about, while Diva tended to stab people.
- BNA: Brand New Animal eventually reveals that Michiru and Nazuna were transformed into beastmen with unusual shapeshifting abilities after an accidental transfusion of modified beastman blood that was used in Sylvasta Pharmaceutical's genetic experiments. It later turns out that Michuru and Nazuna's blood can cure the Nirvasil syndrome ravaging Anima City, without suppressing the Beast Factor like Sylvasta's "vaccine".
- Coppelion has Aether, an injected medicine derived from the Coppelions' blood that grants temporary radiation immunity and enhanced healing. Direct transfusions may not have the same effect, since the Medical Team called a helicopter carrying more Aether instead of attempting a transfusion when short on time.
- In Futaba-kun Change! Misaki gets the temporary ability to turn into a boy when she's transfused with Futaba's blood. Later justified as her latent Shimeru genes (apparently quite widespread in the Japanese population) being activated by Futaba's active genderbending factor.
- Rosario + Vampire
- Humans can be injected with monster's blood, temporarily gaining the powers of whatever monster injected them. Too many infusions will permanently turn the human into that species of monster... with consequences.
- Tsukune receives a few Emergency Transformations from Moka this way, usually as a result of him protecting his friends. Eventually, it becomes permanent; he gets a holy lock from the headmaster, which holds back the feral ghoul in his blood. At the end of the series, he tears off the lock in an act of desperation and discovers it wasn't just holding the ghoul back, it was actually adapting him to the vampire blood; he goes into his junior year a full-blood vampire.
- It's revealed near the end of Season I that the leader of the Anti-Schoolers, Hokuto, was also a human who attended Yokai Academy, and similarly received a life-changing infusion of the same sort.
- Season II reveals this also works in specific monster-to-monster cases. Certain vampires known as 'first ancestors' have abnormally powerful blood, which can only be given to other vampires (or taken from them) by the reception of the first ancestor's blood. When Moka was stillborn, her mother Akasha gave her first ancestor blood to heal Moka, with the side effect of them sharing the first ancestor's power. A fatal blow during the final volume provokes the above-mentioned desperation act as Tsukune returns Moka's favor and gives her blood back to heal her, resulting in the two of them sharing first ancestor power.
- Humans can be injected with monster's blood, temporarily gaining the powers of whatever monster injected them. Too many infusions will permanently turn the human into that species of monster... with consequences.
- Getting bitten by a zombie in Sankarea has this effect: the hydrangea that runs through their veins makes other people temporarily impervious to death or pain.
- The main character of Tokyo Ghoul was transformed into a human/ghoul hybrid due to receiving an organ transplant from a ghoul.
- In the manga Wolf Guy - Wolfen Crest, Akira gives blood to Chiba after Haguro nearly kills him, and Chiba is healed by it and becomes a werewolf — and crazy, with the ability to change at will into some mutated-looking wolf-beast, unlike Akira's transformation. So, not a completely identical transference of abilities, but Akira didn't realize his powers would transfer at all.
- This is Deadpool's backstory; his healing factor is derived from Wolverine's blood. Notably, he was one of many test subjects, most of whom didn't survive, and Deadpool himself suffered some rather severe side effects.
- In Hellboy: The Island, Hellboy gets drained of his blood and a prophet of the Ogdru Jahad absorbs it. This causes the prophet to begin transforming into a copy of Anung un Rama, the demon that Hell wanted HB to be. The man is then driven insane.
- Spitfire of The Invaders gains superpowers from a blood transfusion from the first Human Torch, even though he's an android, because as an Artificial Human he has synthetic analogs to all human parts. In fact, this regularly occurrs as he is a universal donor. Aside from its rejuvenating properties, it's implied that his blood is a catalyst for latent superhuman abilities; Spitfire is implied to be a latent mutant and Toro, his sidekick, has his dormant mutant genes/Inhuman heritage partially activated by a transfusion.
- In PS238, Tyler is cured of an alien virus via a blood transfusion from Julie to briefly give him her super-health, but it has to be removed before the cells started attacking his own.
- In one Rat-Man (1989) story, the protagonist gets Spider-Man's powers this way... and being an incompetent Jerkass, he proceeds to abuse the hell out of them while acting as a jerk. Luckily, it turns out to be Spider-Man's coma dream, and when he awakes it turns out that he got a transfusion from Rat-Man... and thus got infected with his bad luck.
- The Savage Dragon once let his blood be used in an attempt to cure a friend's AIDS. It seemed to work at first — restoring him to full health, making him stronger, even giving him green skin and a fin — but within minutes, he exploded. Years later, after the Vicious Circle steals a supply of his blood from the hospital, their Evil Geniuses figure out a way to keep people alive much longer after being injected. But it turns out that regular doses are necessary in order to keep delaying the explosion, so when Dragon-blood-enhanced supercriminals get arrested, they end up exploding while in custody.
- This is She-Hulk's origin. She needs a blood transfusion and Bruce is on hand; afterwards, she is permanently changed into a Hulk, although she retains her personality and intellect. It later turns out that the Hulk's drastic change in personality is caused by a multiple personality disorder which is exacerbated by his transformation. She-Hulk's personality does change, but instead of going into an Unstoppable Rage like Bruce does, she just gets sassier and more confident. She also doesn't have the insane number of alternate transformations that Bruce does.
- Inverted early on in Spider-Man when Peter gives blood to save Aunt May. Neither of them get much out of it: Peter is too woozy to fight for much of the issue, and his radioactive blood nearly kills Aunt May later on, sparking another "race to find a cure" story.
- In Superman:
- In Superman #6, 1940, Clark Kent opens his own vein to transfuse an injured Lois Lane; not only is she healed of injuries, but the doctor remarks that "his blood conforms to all four types".
- In another Golden Age story, Lois Lane dreams she gets a blood transfusion from Superman and gains superpowers, becoming Superwoman.
- This actually does happen in Action Comics, February 1965. Linda Danvers donates blood (using Red Kryptonite to de-super her arm for this purpose). Her classmate Debbie has a head injury and the blood is used in her surgery. However, her brain damage makes her evil, so now an evil Supergirl flies around freeing crooks and baffling police. Linda catches on when Deb tells her she's read an entire mystery novel in a single night, because altogether human speed readers apparently don't exist. Fortunately super-powers gained this way last only 48 hours.
- In a Bronze Age Superman story, Clark Kent, Lois Lane, and Lana Lang are exposed to alien microbes from a vial that Lana accidentally drops and breaks — the same alien microbes that infected Clark's adopted parents, leading to their deaths prior to his becoming Superman. However, Superman discovers that his Kryptonian immunity system was able to fight off the microbes when he was exposed to them, thus creating a vaccine that he passes on to both Lois and Lana through a blood transfusion that cures them of the microbe infection.
- During the first arc of Young Avengers, Patriot claims that this is how he got his powers: his grandfather, Captain America's supersoldier prototype, gave him a blood transfusion. It turns out be a lie (Patriot was addicted to a drug that gave super-powers), but then he takes a shot from a Kree blaster for Cap. When he gets to the hospital after the battle, Cap is all set for this, except "the other super-soldier beat you to it."
- Infamously, the Marvel Comics Golden Age hero the Whizzer gains his Super Speed powers from a blood transfusion from a mongoose.
- The X-Men member Jonathan "Jono" Starsmore, a.k.a. Chamber, loses his powers during M-Day. This is very bad for him since the first manifestation of his powers destroyed part of his body, including some vital organs, and his power was what kept him alive. However, Jono's family the Starsmores are also a part of Clan Akkaba, descendants and followers of Apocalypse. Clan Akkaba, hoping to convince Jono to join them, gives him a transfusion of Apocalypse's blood. This heals his body and gives him some of Apocalypse's features, such as gray skin, red eyes, and blue lips.
- In Clan of the Mewtwo, a human who receives a transfusion of Mewtwo blood will be transformed into a Mewtwo.
- The Night Unfurls: Chapter 7 of the original reveals that Sanakan and Hugh are given their mentor Kyril's Alien Blood to become empowered hunters. Presumably, this also applies to Lily and Soren.
- Invoked in The Incredible Hulk (2008) by Emil Blonsky, who has himself transfused with Bruce Banner's blood in order to get stronger. Interestingly, he was already an experimental Super Soldier, and Banner's blood interacted with that in a rather unpleasant manner, causing him to become the Abomination.
- Scott from Leprechaun 3 gets some of the Leprechaun's blood in a wound, which causes him to begin mutating into a leprechaun.
- When Megamind finally succeeds at removing his Worthy Opponent Metro Man and is left with nothing to do, he ends up creating a new hero to fight by accidentally injecting some random joe off the street with Metro Man's DNA. This really doesn't work out, though.
- Star Trek Into Darkness: Being injected with Harrison's bio-augmented blood temporarily grants others his Healing Factor, although it's not implied to last beyond the initial healing.
- Unlike in Darths & Droids, this is averted in the canon Star Wars universe. According to Expanded Universe material, it was attempted on General Grievous by giving him transfusions of Jedi blood during his transformation into a cyborg, but he never developed any force sensitivity.
- In David Weber's The Apocalypse Troll, Ludmilla is infected with a parasitic disease that kills 95% of humans who contract it, but gives super-healing and longevity to the few survivors. When Richard is mortally wounded, she gives him a blood transfusion out of desperation. It works.
- Word of God from Rick Riordan, writer of the The Camp Half-Blood Series, confirms that this is not the case in his universe. You cannot gain the powers of Percy Jackson from a transfusion of his blood.
- Averted in The Chronicles of Amber: Corwin states that while he can accept any blood type, ordinary humans really shouldn't receive a transfusion of his blood.
- Downplayed in Dragaera when Morrolan e'Drien receives blood stolen from a Physical God. At the time, it allows him to escape the Paths of the Dead, though he has to do the footwork himself. When he learns Elder Sorcery, the blood helps him manipulate the raw chaos involved without getting liquefied.
- One of the early Hank the Cowdog books includes a silly song about an elderly cowboy who has his youth restored by a doctor replacing all the blood in his body, but then starts acting crazy and getting into trouble. It turns out the doctor accidentally gave him diesel instead of blood.
- In the web-serial Heretical Edge this is how Natural Heretics are created, and the only way to make Heretics before Hieronymus Bosch invented the Heretical Edge. A Natural Heretic gains all the abilities of the Stranger which bled on them, but it takes a while for the powers to grow into their full potential.
- In The Saga of Darren Shan the vampires/vampaneze are recruiting new members to their clans this way. This is usually achieved by both donor and recipient cutting their fingertips on both hands, and keeping their wounds pressed to one another's until the transfused blood has run a full circle between their bodies. While this is the traditional method, injection with syringes also works. A few days later the recipient will turn into a dhampyr or a full vampire depending on the amount of blood transfused.
- In The Secrets of the Immortal Nicholas Flamel, the vampire Scathach gave Joan of Arc an emergency transfusion of her own blood after rescuing her from being burned at the stake. It didn't turn her into a full vampire, but it did make her immortal.
- In Anne Rice's The Vampire Chronicles this is how new vampires are created, with an existing vampire and a human slurping blood from each other with none-too-subtle erotic overtones.
- The 4400 has an inversion. Isabel, the first child born to two returnees, produces pure promycin. When all the other returnees are suffering from an anti-promycin drug, her blood cures Shawn, who goes on to use his own healing powers on everyone else.
- Charmed (1998):
- In the episode "Astral Monkey", Dr. Williamson is experimenting with the Charmed Ones' blood (long story, but he believes it could be the key to a "universal antibody") and unintentionally gives himself and his test subjects (three monkeys) their collective powers (he injected the monkeys with a mix of their blood, and they injected him). Unfortunately, mortals can't properly handle that kind of power, and it starts warping his body and mind; he "does good and saves innocents" by killing criminals and harvesting their organs for those that need them.
- Crossing mortal blood with a magical creature's come back in the episode "Hulkus Pocus", where it creates a deadly virus.
- In Dark Angel, when Max gives an emergency transfusion to Logan, her stem-cell-laden blood starts to repair his spine. Unfortunately, it doesn't last, but he eventually gets a hold of a mechanical exoskeleton that lets him walk again. Later, a transfusion from another transgenic has longer-lasting effects, which when added to the support from the exoskeleton let him be stronger and faster.
- The TV movie Deep Red has a girl whose nanomachine-infused blood rejuvenates the recipient and grants Voluntary Shapeshifting. In a twist, the power only lasts for a limited time, and regular transfusions are needed for people to sustain them. It's because of this that the bad guy, who has some of her blood in his system, is after her.
- In Heroes, Claire's blood can be used to heal other people through transfusion.
- This is what the 1969-71 series The Immortal is all about. The hero is a race car driver whose blood makes him immune to all diseases. An ailing bazillionaire wants him for transfusions, and is determined to capture and enslave him to ensure a lifelong supply of blood.
- In Misfits, Nikki inadvertently gains the ability to teleport by a heart transplant from Ollie. However, she never learns to control it.
- The Outer Limits (1995): In the episode "Last Supper", a Mad Scientist pursues an immortal woman so that he can collect her unique blood and inject it into himself to both heal his own wounds and reverse his aging. He does manage to get hold of it but miscalculates the stuff's potency, eventually shriveling up into a pool of cells.
- In Stargate Universe, Chloe Armstrong is able to cure lieutenant Scott with a blood transfusion in the episode "Cloverdale".
- The Special Children in Supernatural gain psychic powers after the Yellow-Eyed Demon feeds them his blood at 6 months of age.
- In the final episode of Torchwood: Miracle Day, Rex has a transfusion of Jack's blood in order to sneak some into the Blessing site. At the end of the episode, it's revealed that doing so has granted him Jack's immortality.
- Vampire: The Masquerade borrows Anne Rice's method of vampire creation, called "the Embrace". In this case draining the mortal's blood is imperative to transform them into a walking corpse, otherwise they temporarily develop some vampire powers as a ghoul. Vampire blood can be addictive to mortals, and feeding off the same vampire three times binds them to that vampire.
- A running theme in the Fire Emblem series is dragons giving humans their blood in order to empower them, generally giving them the ability to use powerful "Holy Weapons." This always happens in the ancient backstories of each game, though, while the current heroes are descendants of the heroes given the dragon transfusion.
- In Freedom Force, this is how Liberty Lad got his powers; Minuteman gave him a blood transfusion after his Reckless Sidekick behavior got him shot.
- In Iron Twilight, when you get closer to the end of the game, you find out about Felipe's past. Felipe got a blood transfusion from a monster guitar player that got killed in a car accident. Felipe accidentally fell in the puddle of the musical artist's blood, leaving some of the blood to get drained into Felipe's wounds. It was then, Felipe got excellent guitar playing skills and used them to dramatically rank up in the charts. However, he ranks down to the lowest level after Jack kills him in the game's climax (if you make Jack choose to).
- In Mega Man ZX, a "Mega Man" is a Maverick Raid survivor who harnesses the blood of the Big Bad Master Albert via donation. His blood (or rather, the contained DNA) is the key to unlocking the Biometal's power and allowing them to Megamerge with it.
- This may not be a straight example: it's implied that Albert used his influence to get trace amounts of his DNA into everyone through the upgrades that make Reploids and Humans essentially the same. The DNA lets them megamerge, but they still need the biometal to have superpowers. Not to mention the DNA may just be stored as data in both cases (since Reploids and Humans both have machine parts) and is simply submitted as a confirmation code when the person says "megamerge!"
- In the Metroid series, Samus Aran, as a child, was given a transfusion of Chozo blood in order to save her life. This has given her enhanced strength and reflexes (and, presumably, the ability to fit into a ball a third her height). Most importantly, it allows her to make use of Chozo technology, most of which can only be properly used by a Chozo.
- In Operation Darkness, a Werewolf giving his blood to someone changes them and gives them some kind of power... if they survive.
- Late into Tales of Symphonia, Zelos Wilder claims that he has received a transfusion of elven blood, thus solving a cinch in their endgame plan that only a descendant of elves can wield the Eternal Sword. Although he later pulls a Fake Defector gambit (or a proper FaceHeel Turn, depending on the player's choice) and the party acquires a means to let a human wield the Eternal Sword, one of the possible conversations the night before reveals that some elven blood is required for any kind of magic; given that Zelos has a Magic Knight moveset, it's likely he's telling the truth.
- Done deliberately in Darths & Droids; Jim had Qui-Gon give Anakin a blood transfusion so the mini-chlorines [sic] would make him Force-sensitive for the podrace. A later strip says that the Jedi tried it a few centuries ago, but the results were unpredictable, and it is stated that this creates mental instability.
- Tex Avery plays this trope for laughs (natch) in the Walter Lantz cartoon "Crazy Mixed Up Pup". A man and his dog are run over and the paramedics give them transfusions, only the man gets canine plasma and the dog gets human plasma, resulting in a man acting like a dog and vice versa.
- There is an episode of Krypto the Superdog where Streaky the cat gets his powers this way.
- The plot of one Teen Titans Go! episode has the Titans having to deal with their out of control animal urges because they have Beast Boy's blood in them... after he himself can't be bothered to control his own and causes the mess in the first place. When they can't, it falls upon Beast Boy to deal with four rowdy animals.
- In Young Justice (2010), Beast Boy's Animorphism (and green skin), instead of coming from Super Serum as in the comics, is a side-effect of a life-saving blood transfusion from Miss Martian.