I'll come back and post the link if I can find the reference, but apparently real life zombies are somewhat possible. A few years back (2008ish?), I read an article about a German scientist that was able to alter rabies so that humans don't die when they get it. The resulting claim was that they would become super aggressive and attack others, similar to rabid animals, and would create a zombie-like virus. Granted you won't see humans walking around with half their limbs off after dying, but I thought it was interesting how the claim was that it could essentially create a World War Z type of scenario.

Now idk how much of this is true, but I'm almost certain I read it on phys.org, which if I did, would lead me to believe that it's a valid article. I'll see if I can find the link tomorrow.