variant Transmissible Spongiform Encephalitic Necrosis
The downfall of mankind came suddenly, by something even smaller than a virus. The infectious protein, or prion, known as “variant Transmissible Spongiform Encephalitic Necrosis (vTSEN)” was either the result of random evolutionary chance or extraordinarily bad luck. Whichever the case, the end came shortly after a plane touched down in Los Angeles and Patient Zero walked through the airport.
The other major difference and probably the more important, the final terminal stage isn’t terminal. The corpse only remains dead for a short time, but rigor is replaced by violent surges and eventual resurrection. Technically returned to life, these animated corpses are little more than shells of flesh with their minds replaced by a singular, animalistic desire to consume living flesh.