Take the following factoid - Ophiocordyceps unilateralis is a parasitic fungus found in some forests that infects ants in order to spread itself to other plants and trees.
Not that thrilling eh? Now, describe the actions of old Ophio as controlling an army of zombie ants and suddenly we're talking something much more exciting. The zombie factor of this admirably macabre story is upped in the terminal phase of this infection when the Carpenter ants do appear to lose control and latch themselves with a death grip to tree leaves in order to pass on the fungus.
This got me thinking about other things enlivened by a dash of the Undead. Rated in Brains out of 5