Zombies are the result of an attack from a Reaper, they cannot be captured and will mindlessly pursue targets.
Any target, civilian or Xenonaut, who is killed by a melee swipe from a Reaper will immediately become a Zombie. Zombies are slow and only deal a moderate amount of damage per attack (25). But their main threat is not their combat capabilities, but in that if they are killed they will become a fully grown Reaper.
When engaging a Zombie be sure you have enough firepower to not only kill the Zombie but the Reaper that will spawn.
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