Zombies

Zombies come in a variety of forms, raised from the dead by a Greek spell, by the demonic power of Samhain,and even raised by Death himself. Another group of beings that behave in a zombie-like manner are humans infected by the demonically engineered Croatoan virus, and those affected by the Leviathan food-additive.

Real Zombies
When first raised, their memories and personalities may be intact, and they can behave like normal, rational beings for several days before becoming violent and cannibalistic. Methods of dispatch generally involve beheading, staking, or fire. Depending on the zombie, Sam and Dean appear to have varying success with each method. When Sam and Dean first encounter a zombie, a woman named Angela Mason, they seem overwhelmed by the amount of lore on the walking dead and how to kill them:

They shoot Angela in the chest and head with silver bullets, which seems to slow her down but has no lasting effect other than making her angry. Other lore Sam finds suggests "nailing the undead back into their gravebeds," so they lure her back to her grave, and Dean stakes Angela in her coffin, finally dispatching her.

When facing Samhain, he raised several zombies, one who attacked Samhain's vessels students, as such they encounter zombies a second time, Dean stakes two zombies in their coffins to dispatch them.

The next time they encounter zombies is in Sioux Falls, South Dakota, and Sam says that they can be killed with a headshot. Like ghouls, it seems that obliterating their heads can kill them. It is unusual as when Sam shot Angela in the head she recovered fairly quickly, though it may be due to how each zombie was raised.

Croatoan
People infected with the Croatoan virus, called "croats" by Future Dean Winchester, could be classed as zombies as they lose their sense of reason and become unthinking murderous creatures. They are part of the demonic plan for the Apocalypse.

Widespread distribution of the virus is planned using a new vaccine being produced by Niveus Pharmaceuticals, one contaminated with the Croataon virus. The vaccine is being rushed to stem an outbreak of flu caused by Pestilence. This potential disaster is prevented when Bobby Singer, Sam and Castiel blow up the distribution warehouse, although only after battling some zombies. Those infected with the Croatoan virus can also be killed by conventional firearms.

Leviathan Food Additive
The next type of Zombie the brothers encountered, was created by accident as a side affect of the Leviathan plot to control and fatten up the population, 0.03% ended up becoming super strong and agile but also cannibalistic and monstrous.

Real Zombie
Being the walking dead, zombies are incredibly powerful in their strength and agility, and are highly regenerative.


 * Super strength: Are inhumanly strong, are able to easily overpower humans, despite this they're quite weak in comparison to most monsters
 * Super speed: Are awkwardly fast, moving in fast strides.
 * Regeneration: While their bodies can receive damage, they can reform from their injuries.
 * Invulnerability: Although they can be harmed, they are very difficult to re-kill.
 * Death to Vegetation: Down to the unnaturalism of their existence, their presence can cause plants in their presence to wither and die.

Croatoan

 * Super strength - Like their real counterparts, they are stronger than humans.
 * Super Speed - Are faster than humans.
 * Regeneration - Are able to regenerate if injured.

Leviathan

 * Super strength - Just as strong as their counterparts.
 * Super Agility - Able to causally move through the forest.
 * Super Stamina - Don't tire

Real Zombie

 * Head shot: The horseman Death raises the townfolk, back from their graves and turned into Zombies. Sam, Dean, and Bobby kill them by shooting them in the head but they were a different type of zombie.


 * Silver Stakes: Zombies can be killed by driving a silver stake to the heart or by staking them in their graves.


 * Silver Rounds: They can wound, but not kill.

Other
Both other types of zombie are vulnerable to bullets.

Season 2
Angela Mason is raised from the dead by a friend who had a crush on her using an ancient Greek ritual. She goes around killing those who have wronged her. Her presence causes plants in the vicinity to die. Eventually Sam and Dean kill her by luring her back to her grave, and staking her in her own coffin.

Season 4
Samhain raises the Dead from their graves in the mausoleum.

Season 5
Townfolk are raised by the horseman Death and come back perfectly normal, until about 5 days later when they begin to kill.

Season 7
The Leviathans develop a plot to control the population. Dr. Gaines synthesizes a food additive which he has put into turducken which is served in a sandwich at a Biggerson's Restaurant in New Jersey. It is very addictive, and consumption leads to weight gain, and dampens people's emotional responses until they are very apathetic. After cooking, the tainted turducken will revert back to the grey goo state.

However in 0.03% of cases consumption results in "hyper-adrenalised cannibalism" in which people turn become super strong, homicidal and cannibalistic. Dick Roman sees this side effect as a drawback, as it draws attention to their plans, and raises the spectre that monsters do exist.

Season 2

 * Children Shouldn't Play With Dead Things
 * Croatoan (Croatoan Zombie)

Season 4

 * It's the Great Pumpkin, Sam Winchester

Season 5

 * The End (Croatoan Zombie)
 * The Devil You Know (Croatoan Zombie)
 * Dead Men Don't Wear Plaid
 * Two Minutes to Midnight (Croatoan Zombie)

Season 7

 * How to Win Friends and Influence Monsters (Leviathan Food additive)

Lore
Zombie is a term used to describe a hypnotized person bereft of consciousness and self-awareness, yet ambulant and able to respond to surrounding stimuli. Of voodoo origin, the word initially referred to a curse cast by sorcerers (or bokors) allowing them to take control of a person's mind, therefore affecting his or her actions. However, due to significant influence of Haitian Vodou and New Orleans Voodoo on witchcraft mythology, this meaning soon morphed into that of a human corpse mysteriously reanimated to serve the undead. Since the late 19th century, zombies have acquired notable popularity, especially in North American and European folklore.

In popular culture, zombies take a number of forms. There are those raised from the dead by a spell or ritual or reanimated by some supernatural event (such as the movies of George Romero), or people turned into mindless violent cannibals by a virus (such as in the movie 28 Days Later or the Resident Evil franchise). Some are mindless, shuffling monsters, others cunning and quick. Methods of dispatch generally involve beheading, staking or fire.

Trivia

 * There is plenty of lore out there about zombies, the most common one regards staking a zombie in its grave site.
 * In Dead Men Don't Wear Plaid, they don't exhibit regular symptoms at first, but eventually get rabid. In this case, shooting them in the head works.