Starfinder: Infector Zombie
With the massive variety of undead creatures the dark scientists and Necromancers were able to create, they decided they needed a specialized creature – one which could infect a living humanoid and turn the victim into one of many different varieties.
Like most undead, this creature looks like the standard zombie. Grey pallor, visible wounds, vacant eyes and usual blood on the hands or mouth. It is deceiving though, as the creature is incredibly fast, some say just as fast as the Sprinter variety!
The purpose this creature serves is not to kill and consume which is the typical action of a zombie. It has but one goal – to spread the infection. As such it retains enough intelligence to seek out living targets and can easily get into buildings, climb stairs, ladders and even ropes. It can look at a situation tactically and choose the path of least resistance and always avoids targets that are heavily armed – unless it can get surprise.
When the creature strikes, it hits fast and hard, clawing and biting, and as soon as it has drawn blood, it will retreat to search out and find other victims to infect, fulfilling its only purpose in unlife.
If there are multiple targets, the creature will spread its attack between up to three targets at once, attempting to strike each one before running. If it turns out that the creature encounters a group of poorly armed targets, it will stay and strike, attacking each individual in turn until they have all suffered wounds. Once this occurs the creature will then flee, seeking more targets to infect.
Most of these creatures carry the virus to create zombies, but there are those who have multiple viral types in their bite and claw, so the GM is encouraged to choose from the multitude of different types of zombies to infect the hapless victim with.