The zombies are identifiable by the fungi bursting from their bodies: a thicket of spiky tendrils, a miniature garden of mushroom-like fruiting bodies. These fungal parasites act as puppeteers, commanding and positioning the zombies to infect entire communities.

It's the premise of "The Last of Us," a video game series and now a show on HBO, which shares parent company Warner Bros. Discovery with CNN, but it's also a scene that plays out in real life every day around the world.