Shapeshifters have been encountered by hunters and by Sam and Dean Winchester. They are human-like creatures that start out human, but later learn how to change their form to look like anyone they want. When exactly they learn is not consistent, some can learn from infancy, while others do not learn until much later in their lives. Due to starting off as humans, shapeshifters can have human urges and vices, such as greed, lust, etc. They are also arguably the most human monsters there are. Due to having human impulses and desires, shapeshifters are not driven by an instinct like vampires and werewolves and commit their acts by choice.
When a shapeshifter takes the shape of the person they choose, they shed their skin, teeth and nails. When they change into the person's physical appearance, they access the thoughts of the person they are mimicking. Some shapeshifters are known to change their shape in a matter of seconds while others are known to take up to several hours. They can also take the forms of fictional characters or inhuman characteristics, such as vampire fangs or werewolf claws. They can also alter their eyes so they resemble their retinal flare. Some shapeshifters have displayed the ability to seamlessly shift into whoever they want without shedding their skin, similar to their Alpha. In videos and cameras, a shifter's eyes will be a glowing silver-gold color.
Unlike most other monster species, shapeshifters do not appear to be able to sense others of their kind, even when they know the shapeshifter in question. Mia Vallens was unable to tell that her ex-boyfriend Buddy, whom she was specifically trying to escape from, was impersonating one of her patients. Furthermore, even after she knew that he was, she could not identify which one he was for the Winchesters.
While some shapeshifters appear to simply cycle through appearances and never settle on one particular permanent appearance, others of the species appear to have a preferred appearance they use when they are not impersonating another person. Its unclear if this form is simply one they like or, since they are born naturally and grow up like humans, whether its their original appearance. Shapeshifters that are known to do this include the Lassiter Family, Olivia, Mia Vallens and Buddy. In Mia's case, her chosen form is not her original appearance as she stated she changed her face to avoid Buddy. In Buddy's case, he had his chosen form so long that Mia had a picture of him in it.
In Skin, Sam and Dean hunt down a shapeshifter who is turning into peoples loved ones and then killing them. The shapeshifter is killed by Dean.
In Nightshifter, a Shapeshifter started using his abilities to rob banks and jewelry stores in Milwaukee, Wisconsin by studying the patterns of employees or buyers then killing them in an apparent suicide and taking on their form to commit the robberies while presumably hiding in the sewers between the places it robbed.
Eventaully, Sam and Dean Winchester pick up on the pattern and realize they are dealing with a shapeshifter from its retinal flare on a security tape shown to them by former security guard Ronald Reznick it had beaten up who believed it to be a "mandroid." Sam and Dean figure out its pattern and that it's likely to strike the City Bank of Milwaukee next. They identify it as taking the form of the bank manager from the retinal flare the shapeshifter displays in the security cameras, but Ronald, as no one believes him, takes over the bank to stop the "mandroid" and the shapeshifter escapes before Sam and Dean can get it. It then kills another man, hides his body in the celling tiles and takes on his form.After Dean and Ronald find it and lock it in the vault with the other prisoners, the shapeshifter tries to use the excuse of the security guard having a heart attack to escape, but Dean finds its victim's body. Realizing it has been found out, the shapeshifter runs and takes on the form of one of the tellers, Sherri, pretending to be her dead body in hopes that Sam and Dean will kill her and think they had killed it. However, while they initially fall for its trick, Sam figures it out as the real Sherri faints and that wouldn't help it escape. As the FBI and police break in, the shapeshifter attacks Dean and escapes again. Dean chases it to the boiler room where the two fight. Dean eventually manages to gain the upper hand and stabs the shapeshifter in the heart with a silver letter opener, killing it.
In the episode Monster Movie, a shape-shifter is goes a town during Oktoberfest as iconic monsters from the old Hollywood movies. Dean and Sam investigate the several murders. The first victim was found with bite marks on her neck, much like a vampire would leave, while the second victim has wounds that look like a werewolf attack. After a mummy rises from his crypt, Dean determines that it is a shape-shifter. The shapeshifter is later killed by Jamie, who he abducted.
In Two and a Half Men, it is revealed that there is an Alpha Shapeshifter, the first shapeshifter. The Alpha shapeshifter is revealed to be going around make more of his offspring by shapeshifting to women's husband, and then having another shapeshifter abduct it and take it to him. When Sam and Dean rescue one of its children, Bobby John, the Alpha shapeshifter storms the Campbell's compound and kills Mark Campbell, overcoming several gunshot wounds and tranquilizer darts, as well as a silver knife to the heart. It successfully takes it's child and leaves. In Caged Heat the current King of Hell Crowley has captured the Alpha Shapeshifter is held in Crowley's Monster Prison as an effort to the location of Purgatory Crowley tortures the Alpha Shapeshifter on the location of Purgatory but fails to get the information he wants. Enraged, Crowley decapitates the Alpha Shapeshifter, killing him.
In Blade Runners, At some point, Cuthbert Sinclair, a rogue Man of Letters , captured a shapeshifter for his "zoo" where he held a variety of supernatural creatures. When Sam Winchester managed to access his secret lair, Magnus released the shapeshifter to trick Sam, having it take on his own form to lure him into the room where Magnus and Dean Winchester were. The ploy worked and Sam was caught by surprise. The shapeshifter took on another shape and attacked Sam, but Sam quickly recovered and stabbed it in the heart with a silver knife, killing it.
In Ask Jeeves A women named Bunny LaCroix had an affair with a shapeshifter and got pregnant with Olivia. Though Bunny passed Olivia off as her husband Lance's, Olivia's real father came for her after she was born. He killed Lance when he tried to stop him but before the shapeshifter could take Olivia, a hunter named Bobby Singer killed him. At Bunny's pleading, Bobby agreed to spare Olivia on the condition that Bunny lock her up for everyone's safety. Bunny pretended she lost Olivia and locked her in the attic of her house, however, she remained devoted to Olivia and Olivia to her, only letting her butler Phillip know the truth.
After Bunny dies, Phillip takes pity on Olivia and releases her from the attic, giving her a job as a maid in the house as her cover. When a maid named Colette tries to steal a pearl necklace, Olivia takes on the form of her mother and kills Colette. Phillip covers up Colette's death by locking her body in the attic. When Bunny's family arrives for her funeral and will reading, Olivia decides to kill them all as she is disgusted with them for their greed and disrespect for her mother. Sam and Dean also show up, and she decides to kill them both too. She begins killing off Bunny's family one by one.
While Sam and Dean are trying to figure out which of the family is the shapeshifter, Olivia drowns Detective Howard in the toilet and confronts her family with his gun, explaining herself to them. Before she can murder anyone else, Sam and Dean break free by shooting out the lock of the room they are locked in. Olivia and Sam engage in a fight both trying to kill each other. She was then shot through the heart by Dean from behind with a silver bullet, killing her.In Inside Man, Dean has a flashback of killing Olivia while under the Mark of Cain's influence
In Nihilism, a grace-enhanced shapeshifter impersonates the hunter Tiger in order to get into the Men of Letters bunker with several other monsters. During the battle that follows, all five monsters are disintegrated by Jack.
In The Heroes' Journey, the Winchesters, now reduced to normal people by God, investigate a monster fight club led by Cutty, a shapeshifter. Cutty intends to pit the Winchesters against Maul, a massive vampire, but they are rescued by Garth who blows up the club with C4, killing everyone inside, including Cutty.
Powers and Abilities
- Shapeshifting - Shapeshifters can take on a living or dead person's physical appearance by shedding their skin. When they shift, they literally become the person they're mimicking, gaining everything, including fingerprints and DNA; they can also mimic wounds, even very serious ones. Once a Shapeshifter transforms into that person, they can access the thoughts and memories of the person they are mimicking provided that the person is still alive. At least some Shapeshifters share their Alpha's ability to change shape without shedding as shown in Bloodlines, and Twigs & Twine & Tasha Banes. One shapeshifter show the ability to take the form of humanoid fictional monsters.
- Regeneration - As they change their form easily, Shapeshifters can heal non-fatal wounds, and even replace body parts such as ears or a big piece of skin.
- Telepathy - Shapeshifters have a telepathic link with the people they mimic, making them able to "download" the memory and thoughts of this person as long as she/he is alive, which explains why they keep their victims alive.
- Voice Mimicry - The shapeshifter Buddy was able to mimic Dean Winchester's voice without taking on his form as well. However, this was after Buddy had briefly assumed Dean's form.
- Super Strength - Even though they appear human, shapeshifters do possess amazing physical strength. They can easily overpower and kill human beings. One was able to rip a woman apart with his bare hands while in the form of a young child.
- Invulnerability - Shapeshifters are unaffected from most physical injuries, unless caused by silver. One recovered almost immediately after Dean punched him in the face and later after he kicked it.
- Super Speed - Shapeshifters seem to be able to run faster than humans; on several occasions, shapeshifters have managed to easily escape from pursuers. One was able to run faster than a gun could be aimed.
- Super Agility - They possess quicker reflexes than typical humans. One of them was able to dodge a bullet, jump out of a house without hurting itself, and left a bloody footprint on a telephone pole, indicating that Shapeshifters can climb.
- Silver - They can be killed by a silver bullet or silver blade to the heart. Injuries caused by silver are incredibly painful to them while contact with a silver object will burn a shapeshifter and can be used as a method of identification of one.
- Retinal Flare - They are identified by a retinal flare that shows when they are filmed or when light rays cross their
- Iridium - Capable of harming shapeshifters as discovered by Crowley during experiments to find a way to harm the Alpha Shapeshifter.
- Vamptonite - Edgar states that the Leviathan additive is engineered to kill shapeshifters in addition to vampires and ghouls.
- Pepper Spray - Jamie once used it against one to temporally blind him. However, he recovered from it faster than humans would.
- Dogs - Like certain supernatural phenomena, certain animals such as dogs can sense Shapeshifters regardless of the form they take. The sight of one turned one dog from harmless to vicious, while the Alpha Shapeshifter's presence caused multiple dogs to howl. This does not seem to apply on all shapeshifters though, as some were seen near dogs and those remained perfectly calm.
- Decapitation - Since decapitation can kill the Alpha, it is most likely that decapitating a shifter would kill it.
- Heart Extraction - Shapeshifters can be killed by having their hearts ripped out as demonstrated by Irv Sokolowski in Bloodlines when he killed Sal Lassiter by ripping his heart out, albeit with a homemade silver claw.
- Explosions - Garth Fitzgerald IV once blew up an entire monster fight club with C4, killing Cutty and almost all of them (about 58-60 monsters of many species), with only one survivor.
- Alpha Shapeshifter (deceased)
- Bobby John (unknown)
- Bobby John's Father (deceased)
- Crowley's Shapeshifter Test Subjects (deceased)
- David Lassiter
- Magnus' Shapeshifter (deceased)
- Movie-Monsters Shapeshifter (deceased)
- Margo Lassiter
- Olivia (deceased)
- Olivia's Father (deceased)
- Robbery Shapeshifter (deceased)
- Sal Lassiter (deceased)
- Serial Killer Shapeshifter (deceased)
- Captured Shapeshifter (presumed deceased)
- Mia Vallens
- Mia Vallens' mother (unknown)
- Buddy (deceased)
- Tiger Impersonator (deceased)
- Cutty (deceased)
- Season 1
- Season 2
- Season 4
- Season 6
- Season 8
- We Need To Talk About Kevin (mentioned only)
- Season 9
- Season 10
- Season 11
- Love Hurts (mentioned only)
- Season 12
- Season 13
- Season 14
- Season 15
- Bobby Singer's Guide to Hunting (non-canon, mentioned and photo)
- Supernatural: The Men of Letters Bestiary: Winchester Family Edition (non-canon, mentioned only)
- Hunters usually shorten shapeshifter names to just "shifters."
- While shapeshifter is something of a general term, even shapeshifters call themselves by it showing that its the species name, not just a term used by hunters. This is best seen in Bloodlines when David Lassiter calls himself a shapeshifter when talking to Ennis Ross.
- Shapeshifters sometimes make their lairs in the sewers.
- It's unknown what shapeshifters really look like, but claimed to be monstrous and deformed. In Supernatural: The Animation episode The Alter Ego, the shapeshifter reveals his true form. The creature appear to be humanoid insect-like form with green skin, thin body and fingers, large mouth with thick purple lips and little green eyes on the coast of their head. They also have sharping vertebrate outgoing from their back. This is anime-only. Given the revelation that shapeshifters are born, a shapeshifter's true appearance is likely human. In The Big Empty, the shapeshifter Buddy was shown transforming back from Dean Winchester and when he peeled off his copy of Dean's face, his usual appearance was beneath it, albeit bloody.
- Although they have never been seen doing, or implied they intended to, it has been indirectly stated that at least some shapeshifters eat humans, much like several other monsters, as in There Will Be Blood, Edgar said that: "our additive kill werewolf, shifters and the disgusting things that eat corpses. Anything that taste for humans".
- Shapeshifters, along with rugarus, are one of the few monsters shown so far that reproduce almost solely by sexual contact with a human. The offspring that results is assured to be a shifter.
- It's indicated that some shapeshifters may have a preferred form as the shapeshifter in Blade Runners and the Lassiter family in Bloodlines all returned to one particular form after finishing with their shifting activities.
- One shapeshifter has shown the ability to change only his hair.
- In the past all shapeshifter transformations (excluding the alpha) involved the shapeshifter's skin getting peeled/ripped off. However, in Blade Runners, a shifter is shown to seamlessly transform without shedding its skin. This ability was seen again in Bloodlines. VFX I/O Coordinator Adam Williams revealed he was puzzled at why this was. "No idea.. I kinda wondered the same myself. Originally I assumed there were "skin walkers" and "shape shifters" and the skin walkers shed their skin - then I read the superwiki and realized the Alpha can transform without a skin shed but they are all the same monster. I guess sometimes legacy changes."  Later shapeshifters have returned to shedding their skin to transform.
- It is unknown how shapeshifters acquire the clothing needed to look like a person they're imitating. Some simply kill/knock out an intended target and steal their clothes.
- Dean has been mimicked by the Alpha Shapeshifter, the Serial Killer Shapeshifter and Buddy.
- In the non-canon book Bobby Singer's Guide to Hunting its stated that a shapeshifter can give birth to a human since Charles Douglas, a shapeshifter, had a unnamed twin brother that was a human. Although it's unknown if the brothers had only one shapeshifter parent or not, or if that can influence the species of the baby.
- Of the shapeshifters killed on the show, Dean has the most kills of the Winchesters.
- On two different occasions in Season 10's Ask Jeeves and Season 13's The Big Empty, what was suspected to be a ghost turned out to be a shapeshifter.