Scientists have identified four new species of brain-controlling fungi that turn ants into zombies that do the parasite's bidding, before it kills them.  The original zombie-ant fungus, Ophiocordyceps unilateralis, was first identified in 1865, and it seems to exist around the world. 

Once it infects an ant, the fungus uses as-yet-unidentified chemicals to control the ant's behavior.  At solar noon, it "directs" the ant to leave its colony and bite down on the underside of a leaf — the ant's soon-to-be resting place and the place most ideally suited for the survival of the fungus. Once it is killed by the fungus, the ant remains anchored in place, thanks to its death grip on the leaf.

Ultimately, the fungus produces a long stalk that protrudes from the ant's head, shooting spores out in the hopes of infecting other ants. Two of the four newly discovered species also sprout smaller stalks elsewhere, including from the victim's feet and lower leg joints – the equivalent of knees.