Vengeful Spirits

Dean traps Bloody Mary in a mirror

A vengeful spirit is one that acts violently to avenge something a wrong done to them. While they 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.

In episode 2.01 In My Time Of Dying, as Dean is unable to return to his comatose body, the reaper Tessa describes how vengeful spirits are created:

Tessa: "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."^2.01

See also Ghosts

Vengeful Spirits in Supernatural

• Peter Sweeney, in 1.03 Dead in the Water takes revenge on those who drowned him, and their families.
• 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.
• Cyrus Dorian's spirit possesses his truck in 1.13 Route 666 and attacks those responsible for his death, and their families.
• Jonah Greely in 2.16 Roadkill takes revenge on drivers.
• Callie in 3.05 Bedtime Stories causes deaths because her father won't accept that she was killed by her step-mother.
• The Rise of the Witnesses is one of the one of the 66 Seals that when broken, will unlock and open the "door" to 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.
• 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.
• Rose Brown in 6.14 Mannequin 3: The Reckoning takes revenges on the work colleagues whose bullying led to her death. She is able to move around wherever her sister Isabel Brown goes because she received one of her 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 killed before she does it.
• Bobby becomes obsessed with killing Dick Roman, injuring Charlie 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 posseses Louise to kill Dick, but regains control when he nearly kills Sam and at his request, his flask is burned and he is put to rest to prevent it from happening again.

Dispatching Vengeful Spirits

• 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.
• The boys commonly dispatch a spirit by salting and burning its corpse.
• 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 in 1.19 Provenance, the lock of Dirk McGregor's hair in 4.13 After School Special, or P.T. Sandover's gloves which contain skin cells.
• Spirits can be attached to an object: Mary Worthington was trapped inside a mirror in 1.05 Bloody Mary, and in Bobby is attached to his whiskey flask.
• Vengeful spirits may be at rest once they are avenged or heard (i.e. Peter Sweeney and Callie).
• It's unclear where dispatched ghosts go to. In 2.16 Roadkill Sam admits "My dad always said it's like death for spirits. But the truth is, we never know." Dean tells Melanie Golden in 7.07 The Mentalists that burning a ghosts bones may be painful for it.