There is a type of fungi (I think it's a fungi?) that kills ants and then takes over their brains, making eat and living within the ant, essentially making them some type of "zombie". However, a zombie is defined as
the body of a dead person given the semblance of life, but
mute and will-less, by a supernatural force,usually for some evil purpose.
So it's not exactly a 'supernatural force' and not used for evil purposes but it does connect with the first bit of the definition.
If that disease/fungi adapts, develops and evolves onto humans, zombies could sort of be real.
Lol, thank you Vsauce3. ;3