The Cordyceps fungi are unflinching creepy parasites. The most infamous type – Ophiocordyceps unilateralis – attacks just one variety of ant, seemingly possessing them and causing them to climb up through the canopy and onto the underside of a leaf. The fungus then quickly replicates within its hosts, devours the brain, and erupts fresh spores out of the ants' heads.

Although this particular fungus was first discovered way back in 1859 by renowned naturalist Alfred Russel Wallace, it’s still unclear how the fungus actually takes command of the ants. Now, as revealed in the Proceedings of the National Academy of Sciences, it doesn’t actually go for the ant’s brain. Instead, it infests its muscles.

This means that the ant is likely conscious and cognizant of what’s happening to it as the fungus seeps into its body and forces it to move up a tree. It’s like having your entire body zombified except your head, which is arguably even worse than full-on zombification.

Incidentally, the presence of the fungus throughout the ant represents what the researchers refer to as “collective foraging behavior”. This means that many different strands of O. unilateralis dig around, looking for flesh to consume and muscles to ensnare. All things considered, this hellish fungal beast is far more complex than we thought.

A team of entomologists, led by Pennsylvania State University, were quite rightly fascinated by this terrifying, parasitic fungus. Anything that knows to devour the non-vital organs of its host – in order to keep it alive for as long as possible – is too disturbing not to throw some science at.

The problem, though, is that it’s quite difficult to study the proliferation of the fungus through the ants’ bodies, and as such, a lot of assumptions have been made about it. Most notably, it has been taken as a given that the fungus goes straight for the brain, which gives it control over the ant’s actions.

Unhappy with said assumptions, the team decided to peek into the poor carpenter ants’ zombie bodies just as the O. unilateralis demons had finished navigating them to the underside of a leaf.

Examining the ants just as the fungus began to violently spread throughout their bodies, the team used an incredibly precise scanning electron microscope to see which specific cells had been infested. With the help of a beady-eyed deep-learning algorithm, they succeeded.

“Fungal cells were found throughout the host body but not in the brain, implying that behavioral control of the animal body by this microbe occurs peripherally,” the team explained in their study.

You have to feel sorry for the carpenter ant. Its only protection against this horror is another fungus, one which parasitizes O. unilateralis itself, limiting its ability to reproduce.