If zombies give you nightmares, proceed with caution, because things are about to get real. Maybe there hasn’t been an outbreak of zombie plague – yet – but walking corpses and mind control are not just fictional. They happen in both humans and wildlife every day. From rare psychiatric disorders and cat litter parasites that make humans behave strangely to wasps that poison cockroaches and then lead them around by their antennae like dogs, here are 10 fascinating cases of real-world zombification.

Human Brain-Controlling Cat Poop Parasite

Are parasites in your cat’s litter box turning you into a mind-controlled slave? It sounds far-fetched, but Toxoplasma gondii is no joke. This parasite may be changing connections between neurons in cat owners’ brains, affecting our feelings and behavior, and it has even been linked to schizophrenia. It’s the microbe that causes the disease Toxoplasmosis, which can cause serious damage to fetal brains – that’s why pregnant women aren’t supposed to change the kitty litter. The effect in an animal host is clear: once transmitted, the parasite needs to get back to the cat in order to reproduce, and this is where the behavior modification is thought to come into play. Mice and rats that are infected with T. gondii present bizarre behavior that makes them easy prey: becoming attracted to the scent of cat urine, and running fast to get the cats’ attention. But researchers aren’t yet certain just how the behavior modification mechanism works in humans.

Jewel Wasps that Walk Cockroaches Like Dogs

When stung by the parasitic jewel wasp, cockroaches actually lose all free will, mindlessly allowing the wasps to lead them around by their antennae like dogs on leashes. The wasps pull the cockroaches into their underground lairs and lay their eggs inside the roaches’ abdomens. When the larvae hatch, they eat their hosts’ bodies from the inside out – while the roaches are still alive. The mature wasps emerge from the roaches’ bodies after about a month.

Walking Corpse Syndrome

People with Cotard’s Syndrome, otherwise known as Walking Corpse Syndrome, aren’t really zombies – but they think they’re dead. This rare neuropsychiatric disorder is thought to result from a disconnect between the areas of the brain that recognize faces, and the areas that associate emotions with that recognition. The sufferer may not recognize their own face in the mirror, even though they still know who they are. These people may believe that they don’t exist, that their brains are still alive while their bodies are decaying, or that they have lost their blood or internal organs.