Sounds like something out of a horror movie, but it's real. Zombie ants are being infected by tropical fungus, that sits in their brain and then flows through the body tearing up muscle fibres and rendering the body useless.
"The fungus - Ophiocordyceps unilateralis - literally takes over the ant’s brain, filling their head and body with the deadly bacteria until their muscles atrophy, tearing muscle fibres apart.
Uneffected carpenter ants usually walk in a trail, but the fungus attacks the ant’s central nervous system, making it stray from the path and take random routes back to base, unable to find its way home.
The carpenter ants - which usually dwell a top the high canopies of forest regions - then suffer convulsions and fall to the “leafy understory” of the forest, where cooler, moister conditions than the canopy provide an ideal atmosphere in which the fungus can thrive.
The fungus takes control of the ant’s motor abilities, forcing it to bite into the main vein in the underside of a leaf, killing it, but not before giving it a permanent case of lockjaw .
The multiplying fungus cells in the ant’s head cause fibres within the muscles responsible for opening and closing the anti’s mandibles to become detached.
It results in a lock jaw which remains even after the ant is dead, meaning that the symbolic leaf remains within the clenched jaws of the dead ant forever."
There is some merit in to parasites attaching to a host's brain and causing all sorts of problems, as has been the case in life since organisms were incepted.
Perhaps there is something to zombie movies after all.