Dean. How do you think angry spirits are born? They can't let go and they can't move on. And you're about to become one. The same thing you hunt.
A vengeful spirit is one that acts violently to avenge a wrong done to them. While vengeful spirits are generally ghosts, the spirit may belong to someone still alive but close to death, such as Callie in 3.05 Bedtime Stories. This group does not include the spirits of people continuing acts of evil that they perpetrated while alive, like the Hookman Jacob Karns or serial killer Dr. H.H. Holmes, or those acting for their own ends like Maggie Thompson in 2.11 Playthings.
Although vengeful spirits can choose to target those who have committed crimes against others, their judgements can be warped by their time spent dead; as an example, a ghost who targets those who kill family members cannot distinguish between brothers who killed their father to collect on his life insurance or a girl whose cousin died in a car accident where she was driving.
It was initially unclear where dispatched ghosts go to. In 2.16 Roadkill Sam admits, "[M]y dad used to say that was like death for ghosts, you know? But... The truth is, we still don't know. Not for sure." Dean tells Melanie Golden in 7.07 The Mentalists that burning a ghost's bones may be painful for it. Bobby also expressed to Annie Hawkins the belief that this is death for spirits, though he told Sam and Dean that he'd see them on the "other side" before being put to rest himself. In 8.19 Taxi Driver, it is revealed by rogue reaper Ajay that reapers collect spirits once their remains are burned and they are taken to what is supposed to be their final resting place. However, if the reaper is influenced by an outside source such as Crowley, the soul may be taken somewhere else instead.
Vengeful Spirits in Supernatural
- Peter Sweeney, in 1.03 Dead in the Water, takes revenge on those who drowned him and their families. When the last man responsible for his death sacrifices himself to save his grandson, Peter is appeased and goes to rest.
- Mary Worthington, aka Bloody Mary, kills people who have been, or feel, responsible for someone else's death after her own murderer was never caught. Destroyed when her own power is rebounded upon her by Dean with a mirror.
- Cyrus Dorian's spirit possesses his truck in 1.13 Route 666 and attacks those responsible for his death and their families. Destroyed when his bones are salted and burned and his truck is lured onto hallowed ground.
- Jonah Greely in 2.16 Roadkill takes revenge on drivers, also targeting the ghost of the woman who was driving the car that killed him. Bones salted and burned by Sam.
- Callie in 3.05 Bedtime Stories causes deaths based on the fairy tales her father is reading to her because her father won't accept that she was 'killed' by her step-mother. Dies and moves on once her father accepts the truth.
- The Rise of the Witnesses is one of the 66 Seals that when broken, will unlock and open the "door" to Lucifer's Cage. The Witnesses are people who have seen, or died at the hands of, supernatural beings. Once summoned by the proper spells, they act in a manner similar to other vengeful spirits but target a specific person with their wrath. Put back to rest by a spell cast by Bobby.
- Dirk McGregor in 4.13 After School Special possesses social outcasts and harms popular kids at an Indiana high school. His spirit is tied to a lock of hair his father keeps in a Bible on the school bus, where he possesses students who travel on the bus. Put to rest when Dean burns the lock of hair.
- Rose Brown in 6.14 Mannequin 3: The Reckoning takes revenge on the work colleagues whose bullying led to her death. She is able to move around wherever her sister Isabel Brown goes because Isabel received one of her sister's kidneys in a transplant. She is dispatched when her sister dies.
- In 7.04 Defending Your Life, Osiris can command the spirits of the dead and cause them to kill. He commands the ghost of Jo Harvelle to kill Dean, but the god is stopped before she does it.
- Bobby becomes obsessed with killing Dick Roman after his death, injuring Charlie Bradbury the computer hacker in the process. Sam and Dean fear he will become a vengeful spirit, unable to control who he hurts. Later he becomes one as feared and possesses Louise to kill Dick, but regains control when he nearly kills Sam. At his request, his flask is burned and he is put to rest to prevent it from happening again.
- In 8.06 Southern Comfort, Vance Collins, aka The Unknown Soldier, becomes a type of Vengeful Spirit known as a Spectre after he is killed by his brother in the Civil War. After his grave is disturbed and his Indian Head Penny is stolen, Vance ties himself to the penny and possesses people, causing them to kill those they have grudges against. Put to rest when Sam, Dean, and Garth burn his bones and Garth melts down the penny after he possesses Dean.
- In 9.07 Bad Boys, Timmy's Mother protects her son from any threats after dying in a car crash, but she starts to go insane from being trapped on Earth and becomes vengeful, attacking anything she sees as a threat whether it is or not. As she is attached to Timmy, Sam and Dean are unable to dispatch her by normal means, but Timmy is able to take control and become assertive, ordering her to move on. Timmy's Mother grows peaceful and moves on on her own.
- In 10.13 Halt & Catch Fire, Sam and Dean encounter Andrew Silver, a man who is seeking revenge against the people who caused the fatal car accident he died in. Due to the way he died, Andrew exists in the WiFi and has been cremated, so salting and burning won't work. Andrew kills three of the four people responsible, but his wife speaks to him through FaceTime and convinces him to let go of his vengeance and move on.
- In 10.16 Paint It Black, Sam and Dean encounter the vengeful spirit of a nun named Isabella who murdered the man she loved in 1520 after finding him in bed with another woman and who was burned at the stake as a witch. Her personal possessions having been sent to a church in Worcester, Massachusetts, including a painting containing her blood and crushed-up finger in the pigment, Isabella began murdering unfaithful men. Sam burns the painting, putting her to rest.
- In 11.07 Plush, the Winchesters face the vengeful spirit of Chester Johnson, a children's party performer who manifests by possessing people through his old costumes. Chester was accidentally killed by Stan Hinkle and Phil Evans after they accused Chester of molesting their kids, and he targets them and his sister for revenge. Though Chester succeeds in killing Stan and Phil, he is stopped from killing his sister. Chester's spirit is laid to rest when Sam, Donna Hanscum, and Doug Stover burn all of the costumes that he is attached to.
- In 11.23 Alpha and Omega, Sam and Dean face numerous vengeful spirits at Waverly Hills Sanitarium while trying to gather souls to build a weapon to destroy the Darkness. The Winchesters manage to trap the ghosts in a crystal provided to them by Rowena and they, along with other souls pulled from the Veil by Billie, are transferred into Dean. God later extracts all of the souls from Dean after making amends with his sister.
- In 12.03 The Foundry, after meeting the ghost of Lucas Kellinger, the Winchesters suspect that they are dealing with mylings, the vengeful spirits of children who lure adults to their death. However, the true culprit turns out to be Hugo Moriarty, a man who went insane after his daughter's death, committed suicide, and as a ghost murdered children and trapped their spirits in his former house.
- In 12.06 Celebrating the Life of Asa Fox, Asa Fox faces an unnamed vengeful spirit on one of his first hunts after becoming a hunter.
- In 12.13 Family Feud, Sam and Dean encounter Fiona Duncan, who takes revenge upon teachers due to her own teacher not only failing to protect Fiona from being brutalized by the crew of The Star, but encouraging the brutal acts. To prevent Fiona from becoming a vengeful spirit, Gavin MacLeod returns to 1723 to protect Fiona on The Star and die with her when the ship sinks, as he originally did before Abaddon intervened. After Gavin returns to 1723, Fiona's murder spree is erased from existence, proving that Gavin succeeded in preventing her from becoming a vengeful spirit.
- In 13.16 Scoobynatural, the Phantom Ghost Kid becomes a Vengeful Spirit due to his anger and loneliness after being used by the greedy real estate developer Jay. The boy sucks the Winchesters and Castiel into Scooby-Doo before being trapped with the help of the Scooby Gang. After becoming trapped, the boy reverts to his regular form and personality and explains what happened to him before helping to trick the Scooby Gang into believing that ghosts aren't real. Upon their return to the real world, the Winchesters recover the pocket knife the ghost is attached to and melt it with a blowtorch, putting his spirit to rest, but not before promising that they will take care of Jay.
Dispatching Vengeful Spirits
- The boys commonly dispatch a spirit by salting and burning its corpse.
- Sam appears to push the spirit of Dirk McGregor out of a high school student by pouring salt into his hand and filling or covering her mouth with it in 4.13 After School Special, although this doesn't destroy it. In 11.07 Plush, Dean is able to force the Vengeful Spirit of Chester Johnson out of a young woman he is possessing by shooting the Chester-possessed woman with rock salt. The Winchesters later free an old man and a young boy from the same ghost by pressing an iron railroad spike to the host's bare skin which expels Chester.
- In some cases, even if the corpse is destroyed, some remnant of bodily material may remain which must be burned. Examples include an antique doll containing some of Melanie Merchant's hair in 1.19 Provenance, the lock of Dirk McGregor's hair in 4.13 After School Special, P.T. Sandover's gloves containing skin cells in 4.17 It's a Terrible Life, or Isabella who was attached to a painting which contained her blood and crushed bone in the pigment.
- Spirits can be attached to an object: Mary Worthington was trapped inside a mirror in 1.05 Bloody Mary, Bobby was attached to his whiskey flask, Vance Collins was attached to his Indian Head Penny as well as his bones.
- Vengeful spirits may be put to rest once they are avenged or heard (i.e. Peter Sweeney and Callie).
- If a vengeful spirit is on Earth for a particular reason, such as protecting a specific person, if they calm down enough, they may be able to move on on their own such as Timmy's Mother.
- Sometimes a loved one of a vengeful spirit can talk them out of revenge and into peace such as in the case of Andrew Silver.
Vengeful Spitits in Lore
In Jewish mythology, a malicious possessing spirit is known as a dybukk. They are believed to be the soul of a dead person, who can possess the body of a living person. They usually leave after they have accomplished whatever task they need to (Source).