Ghouls are a race of supernatural creatures that have been encountered by Hunters such as Sam and Dean Winchester. The first time Sam and Dean have encountered them was when they took on the form of their long-lost half-brother Adam Milligan and Adam's mother. They also appeared when Crowley attempted to have Sam and Dean fed to a pair of ghouls.
Ghouls are scavenger creatures that live in graveyards and traditionally feed on the flesh and blood of the dead. At times ghouls will change their diet and will feed on living humans instead of the dead. Ghouls can also take the form of any person they have eaten, whether the person is still alive or already dead.
The only thing that can kill a Ghoul is decapitation or complete destruction of the head.
- Shapeshifting - Ghouls have the power to transform into any human. This can only be done by eating a living or a corpse of a human being. Like Shapeshifters, Ghouls also obtain the memories of the person they are mimicking.
- Super speed - Ghouls are said to move faster than humans, at least enough to escape unseen after a surprise attack. In the episode Two And A Half Men, after battling a monster in human form that moved with super human speed, Sam listed down what creatures can move with supernatural speed; ghouls were first on the list. Sam and Dean learned later that they were hunting shapeshifters and the Alpha shapeshifter.
- Super strength - Ghouls are stronger than humans. They can overpower a human, but can also be fought off. In "Caged Heat", Dean was able to temporarily hold off two ghouls without using guns or other kinds of weapons. As such they are amongst the weaker monsters.
- Enhanced durability - Ghouls are more durable than humans, one was able to take a shotgun shot to the torso and was only stunned. However, they are far from invulnerable.
- Decapitation - Complete removal or destruction of the head is lethal to a Ghoul.
- Vamptonite - Edgar states the Leviathan additive will kill ghouls as well as vampires. (There Will Be Blood)
- Extreme Brain Damage - Enough damage to the head, even without decapitation, can kill a ghoul.
- In popular culture, the word "ghoul" is often used for an undead creature that eats freshly buried corpses. In Supernatural, however, ghouls are not undead but a type of monster.
- The actual Ghouls in Islamic lore aren't always dead, and are often a devilish form of Jinn or demon, believed to be sired by Ibilis.