Zombies are a staple of horror fiction because they speak to our primal fears. Death is frightening enough; the thought of the dead rising up against the living, and the living losing control of their bodies and minds as they become undead, is the stuff of nightmares. Like vampires, another classic creature of horror, zombies exist in the Star Wars universe. Their characteristics and origins are not always the same, but there is generally an effort to explain them scientifically.
The first mention of zombies in the Star Wars universe was in the young readers novel Galaxy of Fear: City of the Dead by John Whitman (1997). The story takes place on the planet Necropolis, which means "City of the Dead." The planet's inhabitants have a superstition that if the dead aren't treated with respect, they will rise from the grave.
The mad scientist Dr. Evazan uses the planet's superstitions to his advantage while conducting his experiments on the reanimation of dead tissue. His reanimation serum can create zombies which obey his every command. The serum even allowed Evazan to fake his own death and then come back to life to finish his experiments.
Bodies that were dead a while before being reanimated fit the stereotypical appearance of zombies: rotting, shambling, and unintelligent. Zombies created from the newly dead, however, merely look ill. They are intelligent enough to communicate, although their reaction time is slow.
The idea of zombies arising from an immortality experiment returned in the novel Red Harvest by Joe Schreiber (2010). In that story, Darth Scabrous uses a black orchid to create zombies as part of his quest for the ultimate Sith goal: eternal life.
But both Red Harvest and Schreiber's previous novel, Death Troopers (2009), revolve around the idea of a zombie virus. Scabrous' experiment creates a plague known as The Sickness, which spreads through bites and contact with fluids and causes the infected to become zombies. These zombies are the gory horror movie type: single-mindedly violent, hungry for flesh, and immune to pain. Unlike most popular zombies, they can't even be killed by removing the head.
The virus resurfaces over 4,000 years later when Darth Vader learns of Scabrous' experiments. The Imperials' attempts to weaponize the zombie virus is simply called "Imperial bioweapons Project I71A." This virus is airborne and causes flu-like symptoms before the infected person dies and becomes a zombie.
Insects in the Brain
The short story "Gathering Shadows" by Kathy Burdette, which appears in Tales from the New Republic (1999), was the first to suggest a more natural cause for zombieism. The story contains a mention of the "Walking Dead," which occurs when a certain parasite infects the brain of a dead body. The parasites' secretions send signals to the nerves, making the body start walking again. These zombies are creepy but harmless, simply wandering aimlessly until the nerve signals stop.
The idea of zombies created by insects, however, returned in two Season 2 episodes of The Clone Wars, "Legacy of Terror" and "Brain Invaders." The story revolves around a battle on Geonosis, whose native species the Geonosians are insectoids who share a hive mind. With the help of parasites known as brain worms, the hive mind can control the bodies of dead Geonosians, turning them into soldiers who cannot feel pain. The brain worms can also enter and control the minds of living hosts, but as it does not kill its hosts, they are not true zombies.
Only the story "Planet of the Dead" in Star Wars Tales #17 (2003) features zombies that aren't explained scientifically. The story follows Han Solo and Chewbacca as they land on an apparently abandoned planet. After they escape from a zombie attack, one of the planet's natives reveals that the zombies are explorers that died in a crash, who return every night at the hour they died. Han helps the ghost ship land without crashing, which puts the souls to rest and gets rid of the zombies.
This tale seems more like a ghost story than a zombie story, since it involves souls who linger at the place of their death, unable to move on until a problem is set right. Even considering that the comic may not be canonical, it's hard to see how this fits with other Star Wars zombies.
The vastness of the Star Wars universe, however, leaves plenty of room for different explanations and interpretations of zombies. Whether they're violent zombies out for brains or souls who can't get put to rest, zombies add an element of horror to Star Wars.