Many passages in the Christian scriptures describe the belief that demons can indwell or possess a human being and cause them to behave strangely. Much mental and physical illness was attributed to this origin in the earlier eras.
Possession is identified throughout human history and its innumerable religions as the act by an outside force, either demonic or spiritual in nature, of taking physical control of an individual's body or an object. Humans, animals, even places and objects alike are susceptible to these supernatural forces.
To manifest on Earth, demons require a human body. They do not require consent for possession, although at least some demons can only gain access if the human is psychologically vulnerable; one demon was only able to possess a host when its target expressed a fear of flying preparing to travel in an airplane, but Azazel was able to possess a reaper without any sign that she was emotionally vulnerable to his influence. Possession in and of itself can harm a person if the demon remains within the body for too long. While possessed, the human may sustain injuries or even be killed, but possession will continue to animate the body until the demon leaves it.
When Dean becomes a demon, it is because the Mark of Cain has twisted his soul, not because he is possessed. As a result, Deanmon was also immune to exorcism and the anti-possession tattoo on his body, as he wasn't technically possessing his body as it was his own form rather than another's.
Variations on spiritual possession can be found in the following episodes:
- 1.01 Pilot - The Woman in White, Constance Welch takes possession of the Impala and tries to run down Sam and Dean.
- 1.07 Hook Man - The spirit of Jacob Karns, a murderous preacher lives on through what remains of the hook he wore in life, latching on to the repressed emotions of a preacher's daughter who wore part of the hook as a necklace.
- 1.19 Provenance - The spirit of a long dead murderous child, Melanie Merchant and her guilt ridden father literally possess a painting done of their family. This was the second example of a spiritual possession of an inanimate object (although some might think of this as more of a haunting than a possession).
- 4.13 After School Special - The spirit of Dirk McGregor possesses students that are being bullied and uses them to attack others, having latched on to the students who travel in the bus his father drives due to his father keeping a lock of his hair in a Bible.
- 6.14 Mannequin 3: The Reckoning - The spirit of Rose Brown possesses an anatomy dummy, a mannequin, and a Real Doll, using all three to kill men complicate in her death. Her spirit then possesses the Impala and attempts to kill Dean, but instead accidentally kills her sister, Isabel Brown.
- 7.22 There Will Be Blood and 7.23 Survival of the Fittest - Bobby possess a woman, Louise and uses her to try and kill Dick Roman.
- 8.06 Southern Comfort - Vance Collins the spectre of a Civil War soldier, possess people who handle one of its possessions, a penny, and cause them to kill people they hold grudges against.
- 10.16 Paint It Black - The spirit of a nun named Isabella begins possessing and murdering people who have confessed to sins of infidelity at a church in Worcester, Massachusetts.
Demonic possessions are listed below. Beginning in season three, incidents of demonic possession escalated rapidly.
- 1.04 Phantom Traveler - A demon possesses a passenger and causes the crash of an airliner. The demon seeks to finish the job when there are survivors. Sam and Dean are forced to board a plane and perform an exorcism, upon being forced out of the body of the co-pilot, the demon briefly takes possession of the plane until Sam is able to finish the exorcism rite, sending the demon back to Hell.
- 1.22 Devil's Trap - It's revealed that Meg Masters is actually a girl possessed by a demon who is exorcised by Sam which kills the real Meg. John is also possessed in this episode, by Azazel, and is able to temporarily regain control of his body while possessed. Azazel eventually flees his body after Sam shoots him with the Colt, but hesitates to kill him. Several other people are possessed during the episode including Tom who is killed by Dean.
- 2.01 In My Time of Dying - Azazel possessed the reaper, Tessa, and a janitor in the hospital (as he was communicating with John). Several other hospital staff appeared to also be possessed in this scene, as they exhibit the demonic black eyes.
- 2.08 Crossroad Blues - The Crossroads Demon in this episode was possessing a woman. She eventually abandons the woman after breaking Evan Hudson's contract.
- 2.09 Croatoan - Duane Tanner appears to be possessed much like Meg Masters was. The residents of River Grove, Oregon in this episode did not exhibit the usual signs of possession (such as the 'black smoke' upon death).
- 2.14 Born Under a Bad Sign - Sam is possessed by Meg. She tries to convince Dean that Sam is turning evil, but he recognizes that Sam is possessed. Dean and Bobby try to exorcise Meg, but she has placed a binding link on Sam's body. Bobby must burn the link with a hot fire iron so that the possession can be ended. Meg flees Sam after the brand is broken, but is still out there somewhere as she is not exorcised. Bobby provides the brothers with anti-possession charms.
- 2.21 All Hell Breaks Loose: Part One & 2.22 All Hell Breaks Loose: Part Two - The Yellow-Eyed Demon returns, still occupying the body of the janitor from 2.01 In My Time of Dying. The spirit of John Winchester is able to interact with the demon and pull it out of the body temporarily. The demon returns to his body and is promptly killed along with his meatsuit by Dean with the Colt. A Crossroads Demon also appears in this episode when Dean makes his deal possessing someone else.
- 3.01 The Magnificent Seven - The Seven Deadly Sins, freed when the Devil's Gate in Wyoming opened, possess bodies. Ruby appears and kills several of them with a demon killing knife, while Bobby Singer is able to exorcise the demons from another two victims. Envy is exorcised by Tamara, but the man he possesses does not survive.
- 3.02 The Kids Are Alright - Ruby reveals that she is a demon possessing a body.
- 3.04 Sin City - Demons possess Father Gil and Casey to promote the destruction of a town. Both are killed along with the people they are possessing by Sam with the Colt. Ruby interacts with Bobby.
- 3.05 Bedtime Stories - Sam summons a crossroads demon to discuss Dean's deal, then kills her with the Colt when she reveals she can't break Dean's deal.
- 3.09 Malleus Maleficarum - Ruby appears, as does Tammi, who is empowering a group of witches. Tammi is killed by Dean with Ruby's knife.
- 3.12 Jus in Bello - A large group of demons possess townspeople, as well as Special Agent Victor Henriksen, and trap Sam and Dean in a sheriff's office. Ruby also appears, and tries to convince Sam and Dean to conduct a ritual sacrifice that will kill the demons. Instead, they allow the demons into the building and perform a mass exorcism. Lilith appears later, possessing a child. It is revealed that Sam and Dean now have anti-possession tattoos.
- 3.15 Time Is on My Side - In a flashback, a crossroads demon possesses a child, offering to make a deal with Bela Talbot. Also, Sam and Dean interrogate a demon about who holds Dean's contract and exorcise him eventually, but his meatsuit does not survive.
- 3.16 No Rest for the Wicked - Lilith possesses another child, tormenting her parents, and later takes over the body Ruby is possessing, apparently expelling Ruby in the process. Lilith flees when Sam proves immune to her powers. Lilith's henchmen possess most of the neighborhood.
- 4.01 Lazarus Rising - Ruby returns in a new body. Sam and Dean encounter three possessed people in a diner.
- 4.03 In the Beginning - Dean is sent to the past, and encounters Azazel, who possesses a number of people in order to make deals. He even possesses Dean's grandfather, Samuel Campbell.
- 4.04 Metamorphosis - Sam performs a psychic exorcism on a demon.
- 4.07 It's the Great Pumpkin, Sam Winchester - Samhain is raised by witches, and possesses Don Harding. He is exorcised by Sam's powers.
- 4.09 I Know What You Did Last Summer - Alastair and other demons search for Anna. Sam reveals his encounters with demons in Dean's absence through flashbacks. It is revealed that Ruby currently occupies a body that was comatose and from which the spirit was absent.
- 4.15 Death Takes a Holiday - Alastair returns in two other bodies with several other demons.
- 4.16 On the Head of a Pin - Dean is asked to torture Alastair for information. Sam kills Alastair.
- 4.18 The Monster at the End of This Book - Lilith appears possessing a "comely dental hygienist from Bloomington, Indiana," offering to make a deal with Sam. She flees her body when Raphael arrives.
- 4.20 The Rapture - Demons possess Jimmy Novak's neighbors and wife, trying to capture him; they are all killed by Sam and Dean and Castiel while using the body of Claire Novak except for one that Sam exorcises psychically.
- 4.21 When the Levee Breaks - Ruby returns, and Sam prevents Dean from killing her.
- 4.22 Lucifer Rising - In a flashback, Azazel possesses a priest, Father Lehne, and murders several nuns. Ruby and Sam kidnap a demon possessing Cindy McLellan and torture her to locate Lilith who returns in the body of the dental hygienist. Sam kills Lilith. Dean kills Ruby.
- 5.01 Sympathy for the Devil - Meg reappears with a number of other demons. Bobby is possessed, but manages to temporarily overcome the demon and stab himself to save Dean. The demons with Meg are killed and she flees her meatsuit. Several demons are destroyed at John's lock-up by angels.
- 5.10 Abandon All Hope... - Sam and Dean meet Crowley, a demon who wants to help them stop the Apocalypse. In Carthage, MI, they encounter Meg, who sets hellhounds on them. A number of demons are sacrificed to raise the Horseman Death.
- 5.14 My Bloody Valentine - Demons attend to the Horseman Famine. He is defeated by Sam when he "eats" five demons, and Sam uses his powers to exorcise them.
- 5.20 The Devil You Know - Crowley returns and offers to help Sam and Dean find Pestilence by capturing Brady, a friend of Sam's from Stanford who is possessed. A number of demons work with Brady at Niveus Pharmaceuticals and at least one is killed by Dean. Crowley uses a binding link to keep the demon in the body. After getting what they need, Sam kills Brady. Crowley also makes a deal for Bobby's soul in exchange for locating Death.
- 5.21 Two Minutes to Midnight - Crowley leads Dean to Death, and restores Bobby's ability to walk. Two demons at Niveus Pharmaceuticals attempt to release the Croatoan virus but are killed by Bobby. A demon works with Pestilence, but is killed by Castiel.
- 5.22 Swan Song - Two demons are killed and drained, and Sam psychically kills several more. It is revealed that a number of demons in addition to Brady have been keeping track of Sam by possessing people he knew. They are killed by Lucifer.
- 6.04 Weekend at Bobby's - Bobby has a Crossroads Demon tied up in a devils trap in his basement who he tortures for Crowley's real name. After he gets the information on Crowley he burns the Crossroads Demon's bones, killing it and its host.
- 6.07 Family Matters - Christian Campbell is killed by the Alpha Vampire, but immediately revives with black eyes -- he has been possessed. Other demons arrive to transport the Alpha Vampire, and Crowley appears to speak to the Winchesters.
- 6.08 All Dogs Go to Heaven - Crowley orders Sam and Dean to investigate a series of vicious killings.
- 6.10 Caged Heat - Meg returns and partners with Sam, Dean, and Castiel in an assault on Crowley's monster prison. She has three demons with her, and they encounter Crowley and three other demons at the prison, including the possessed Christian Campbell. All except Meg (and secretly Crowley) are killed.
- 6.18 Frontierland - Two demons possessing cowboys go after Samuel Colt. He kills them with the Colt.
- 6.20 The Man Who Would Be King - Dean, Sam, and Bobby torture Red to find Ellsworth, who is killed by Castiel to keep his friends from finding Crowley. Castiel later kills three demons to protect his friends.
- 6.21 Let It Bleed - Demons kidnap Lisa and Ben; Lisa is possessed, and nearly dies when Dean exorcises the demon from her injured body.
- 6.22 The Man Who Knew Too Much - Crowley and a cloud of demons attack Castiel's angels in an attempt to prevent him from opening Purgatory alone. And in a flashback, Sam killed a crossroads demon.
- 7.01 Meet the New Boss - Crowley is found hiding in an Enochian-layered camper van by Castiel, who instead of killing him, offers him his place of King of Hell under supervision. Crowley is later summoned by Sam, Dean and Bobby for information on a spell to bind Death.
- 7.06 Slash Fiction - Crowley visits Dick Roman, the leader of the leviathans, and offers to broker an alliance. Dick turns him down and threatens to wipe out the demons should he feel inclined. Crowley vanishes.
- 7.08 Season Seven, Time for a Wedding! - A crossroads demon called Guy is brokering deals with humans and then exploiting a loophole by having his associate, Jackson, murder them shortly after. One such deal involves supplying Becky Rosen with the love potion she's using on Sam. The Winchesters attack the demons and Becky kills Jackson. Guy is rescued by the timely arrival of Crowley, who undoes all of Guy's deals in exchange for Guy's life. Crowley reveals he's kept his demons at bay in the hopes the Winchesters might succeed in killing the Leviathans. He then takes Guy back to Hell to make an example of him.
- 7.15 Repo Man - Four years ago, a demon possesses a psychotic postal worker called Jeffrey and murders several women before being captured and exorcised by the Winchesters. In the present, the murders start again and the Winchesters seek Jeffrey's help in understanding the demon's modus operandi. Jeffrey captures Dean and uses his blood to summon the demon with the intent of becoming its meatsuit once again. The demon rejects him, possessing a young man instead and is exorcised soon after by Nora Havelock.
- 8.02 What's Up, Tiger Mommy? - Crowley possesses Linda Tran in order to get the demon Word of God tablet. When Dean tries to kill both Crowley and Linda with Ruby's knife, Crowley flees and returns to his usual meatsuit, leaving Linda catatonic.
- 8.12 As Time Goes By - In order to infiltrate the Men of Letters, Abaddon possesses a woman named Josie Sands who is to be initiated into the order. After being unable to kill the demon, Henry Winchester shoots a devil's Trap-carved bullet into her brain, binding her to Josie. Dean says that he is going to cut Abaddon up into pieces and bury them in cement, forever entrapping her.
- 8.17 Goodbye Stranger - Using Meg, demons under the orders of Crowley search for Lucifer's Crypts. They possess various people including Ann Morton and Wendy Rice to try to find the Crypts, but those demons are killed by Castiel. Meg is killed by Crowley with an angel blade while buying Sam, Dean and Castiel time to escape.
- 8.22 Clip Show - Sam and Dean discover that the Men of Letters recorded every demonic possession for 300 years up until their demise in 1958 including Ichabod Crane and Lizzie Borden. They find that the Men have a rating system with a possession such as the one in The Exorcist being a Class 2 Infernal Event. They discover a film of a Class 5 Infernal Event where two priests, Father Max Thompson and Father Simon attempted a new exorcism to cure a demon and make them human again. The attempt failed and the old woman died while the demon escaped into the world, but Father Thompson continued his efforts, eventually curing one possessing Peter Kent. Abaddon is put back together and reveals that she killed Father Thompson and possessed Josie Sands to infiltrate and destroy the Men of Letters after learning of them and her from him.
- 8.23 Sacrifice - Sam and Dean capture Crowley to use him to for the third trial which is to cure a demon. As Sam works on curing Crowley, he sends a distress call and Abaddon, still possessing Josie Sands' stitched-together body arrives. She wants to kill Crowley and take over Hell, but Sam douses her in Holy Fire causing her such extreme pain she quickly flees Josie's body and the scene. Crowley is nearly cured and shows signs of humanity, but Dean stops Sam before he can finish after learning from Naomi that Sam will die if he completes the trials.
- 9.02 Devil May Care - Abaddon has a demon perform a ritual to restore Josie Sands' body to act as her meatsuit once again. She later exorcises a crossroads demon who questions her and helps three demons loyal to her possess three soldiers to have stronger bodies to use. Sam and Dean discover the bodies the demons had previously used and discover that the people possessed all died of old wounds they suffered while possessed when they were abandoned. The soldiers and the demons possessing them are killed by Gadreel.
- 9.10 Road Trip - At Crowley's suggestion, Dean lets him briefly possess Sam to help him expel Gadreel. Crowley succeeds and willingly returns to his usual body afterwards.
- 9.11 First Born - In 1863, Abaddon possesses Cain's wife Colette to try to get him to rejoin the Knights of Hell. When that fails, Abaddon starts to fatally damage Colette's body, leading to Cain trying to kill her with the First Blade. Abaddon flees at the last moment and he kills Colette instead.
- 9.16 Blade Runners - Crowley possesses Andre Devlin briefly to find out the location of the First Blade before returning to his usual body.
- 9.17 Mother's Little Helper - Abaddon possessing the Mother Superior of a convent and three demons, including one possessing Sister Agnes steal people's souls to create an army of demons loyal only to Abaddon. The other two demons are exorcised by Henry Winchester and Josie Sands, but Abaddon is immune and Sister Agnes is away at the time of the exorcism. At Josie's insistence, Abaddon possesses her instead of Henry to infiltrate the Men of Letters. In the present, Sister Agnes and another demon are killed by Sam.
- 9.21 King of the Damned - Abaddon, still possessing Josie Sands, is killed by Dean with the First Blade.
In season six, the first known instances of monster possession appear.
- 6.16 ...And Then There Were None - Eve creates the Khan worm, which can enter a person's body through the ear and control their actions. The first man possessed, a trucker for the Starlight Cannery named Rick, kills his family while under the monster's control. The Khan Worm then enters another cannery worker and kills six men before Dean, Sam, Bobby, Rufus, Samuel, and Gwen appear on the scene. It then possesses Dean, who kills Gwen; Samuel, who is killed by Sam while possessed; and Bobby, who stabs and kills Rufus. Sam and Dean eventually overpower Bobby and shock him with electricity until the Khan Worm slides out of Bobby's ear and dies.
- 6.21 Let It Bleed - Eleanor Visyak is revealed to be a native of Purgatory who has been possessing the mother of a man named Westborough since the 1930's.
- 7.02 Hello, Cruel World - After the Leviathans take control of Castiel's vessel, it begins to deteriorate, which forces them to abandon his body and disperse in a local water reservoir, by which they manage to spread throughout the town of Stockville, Kansas and take possession of various humans. Some of the higher-ranking Leviathans like Dick Roman possess influential public figures in order to carry out their plan.
- 8.19 Taxi Driver - Rogue Reaper Ajay is approached by Sam and Dean while possessing the body of a Middle Eastern taxi cab driver.
- 9.03 I'm No Angel - Sam and Dean once again come across rogue reapers, the first was named Maurice -- who was tasked by Bartholomew to track the Winchesters in hopes of finding Castiel. The second was April Kelly who offered Castiel shelter as April to gain his trust and to torture information about Metatron out of him.
Brief History of Possession
Though belief in possession is spread throughout the world within various cultures, if you ask most people on the street about possession the concept of demonic possession as understood by the Catholic Church will come to mind. During the Middle Ages cases of demonic possession ran rampant throughout Europe. Exorcisms were common place.
Most people relate the subject of possession to the 1973 horror classic The Exorcist based on the novel by William Peter Blatty. The movie was based on Blatty's novel of the same name that was inspired by the real life story of a young Maryland boy on who an exorcism was performed in 1949 at Alexian Brother's Hospital in St. Louis, Missouri.
Though possession is considered by most as a terrifying prospect there are some religions such as Voodoo that encourage spiritual possession by what are referred to as loa. Modern day doctors and scientists believe that the demonically or spiritually possessed of the past were more than likely mentally disturbed people. Thus possession was an uneducated way of explaining various mental illnesses.