The single-celled protozoan Toxoplasma gondii is a fascinating parasite. Replicating only in cat intestines, it is excreted in feces and subsequently spreads to many other organisms, not just felines. Inside these critters, it winds its way to the brain and transforms into numerous cysts, patiently waiting to return to its desired nine-lived host. But, though dormant, it is not entirely inert. T. gondii actually alters its host’s behavior. Mice, for example, grow less fearful of cats, making them easier prey. Just like T. gondii wanted …
