As a noted zombie expert, people ask me all the time, “Are zombies real?” 
What I usually say is, “Not yet… but… it’s possible.”
There are no human zombies (yet). 
There is no evidence of zombie-like behaviour in apes, mammals, birds, lizards, amphibians or fish…
There are many examples of zombie-like behaviour in the insect world.
And now, according to fossil evidence, we know that…
(I have this thing for sensationalistic headlines)
Yes, my little geeks and nerdlings, zombies have roamed the Earth for at least 48 million years.
Zombie ants, that is.
(Credit: [left, fossil] Torsten Wappler; [right, ant] David Hughes)
Today, there is a certain type of fungus  well known for taking over the minds of ants such as the Camponotus leonardi worker pictured above.
Once infected, an ant wanders away from its colony, bites down on a leaf vein near the forest floor, and dies – creating ideal conditions for the fungal fruiting body that sprouts from its corpse. Only parasitized ants perform this routine , and the bite marks they leave are so distinctive that they’re recognizable even in fossil foliage.
The ancient leaf pictured bears 29 scars that represent the last acts of up to seven ants, probably close relatives of the modern Camponotus zombies.
That makes the leaf the first known fossil evidence of zombie-like behavior in any animal.
 My initial reaction is to say, “What are you, retarded?”
 (Walmart shoppers notwithstanding) It’s just a matter of time. It’s not a case of ‘if’… merely a case of ‘when.’
 Ophiocordyceps fungi.
 I’m not an entomologist (although I play one on the internet) but from what I can tell, such zombie-like behaviour only occurs in cases where an insect is parasitized. That is, another creature (or fungus, in this case) implants its seed/young in the host insect. Once ‘infected’, it completely changes its behaviour pattern in order to benefit the unborn young within it. See articles here (and in our sister blog Kosher Samurai) for modern examples of such zombie-like phenomena in crickets/grasshoppers, honey-bees and ladybugs.