Zombies do exist. Scientists in Thailand have discovered a type of fungus, Ophiocordyceps unilateralis, that infects ants, taking control of their brains. The fungus directs the ant to go where its death would be ideal for the fungus' ability to spread itself. In the meantime, the infection converts the ant's internal tissues into sugars that help the fungus grow.
I also preserves the ant's exoskeleton, in fact reinforcing and sealing it to keep out microbes and other fungi.
All the while, the ant travels long distances, at the direction of the fungus within it.
Zombies exist. They may be insect zombies, but they are zombies nonetheless.
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