The unquiet dead. They have risen from the grave in search of warm human flesh. They transmit their disease via blood-to-blood or saliva-to-blood contact. They commonly shamble and are uncoordinated. Unfortunately, recent mutations in the ZIV-4 complex have enabled muscular tissue and neural response to increase function, despite necrosis. The idea that zombies move slowly is, increasingly, a deadly preconception.
Techniques for dealing with zombies are well-established. The Ministry of Secrets discontinued its Revenant Research Unit in 1983, partially as a result of the events documented in this filmstrip. Zombies are not considered to be a high-priority issue at this time; however, be aware that a mass infection scenario would be extremely grave and survivable only with extremely heavy losses.